Let's go deep into how Mu calculations on HP options and boosters are made! 
On normal level char without HP and set bonuses or ML stats is easy:
Example:
Naked BK HP:858
http://prntscr.com/c5z3n2
Naked BK with ring+4%HP:858*1.04=892.32
http://prntscr.com/c5z8tx
Naked BK with ring 2 rings+4% HP: 858*1.08=926.64 (not exactly like this, but simplyfing)
http://prntscr.com/c5z9dq
(Note that the 4% is applied of base hp, not the one resulting after first ring+hp, or otherwise it would be 858*1.04*1.04=928 HP, which is not the case)
BK with an ancient set that gives +15 vit: 858+15*3=903
http://prntscr.com/c5zari
BK with an ancient set that gives +15 vit and a ring +4% HP: 858*1.04+15*3=937.32
http://prntscr.com/c5zbjv
So yeah, ancient stats are NOT affected by it, because otherwise it would be: 903*1.04=939.32 which is not the case.
Let's move to a ML char.
SM without any HP modifier except from Tree and ML Stats: 30+799+113*2+766=1821
http://prntscr.com/c5zkhx
SM with a ring+4% HP: ( 30+799+15*2)*1.04+98*2+766=1855.36
http://prntscr.com/c5zo88
So yeah, master level HP doesn't get raised by 4% option, but surprisingly (or buggedly lol) Master level HP stats doesn't either
Following the logic of the example before, if we add a 5 ancient parts +5sta: ( 30+799+15*2)*1.04+25*2+98*2+766
http://prntscr.com/c5zpmz
So if we add the last part of my gear (shield with +hp option): ( 30+799+15*2)*1.08+25*2+98*2+766=1939.72
http://prntscr.com/c5zqho
So in general, for any char formula is:
(Base HP
+ Level HP
+ Stamina Points (from stats) HP)
* HP boosters
+ HP from ancient items and options
+ HP from Master Level Stats
+ HP from Master Level HP increase
+ HP from BA/DA items
Things left for testing:
Stats from EE Bless
Vit from earth seed
%HP option from seed
Increase Max Life from ancients
My guess is that all that those will be added at the end without being multiplied (and that %HP from socket will work same way as excellent), but my gear/chars doesn't allow me to test that.
Lets now check how Life sweall(23%) works:
SM with ancient set, but no ring +hp or shield: ( 30+799+15*2)*1.23+25*2+98*2+766=2068
http://prntscr.com/c603u3
Notice that the correct way to add this HP % increase options is actually like this (But I simplified on the examples avobe because the results didn't change at all)
30+799+15*2)+25*2+98*2+766 (1871)
HP Sweal: ( 30+799+15*2)*0.23=197.57 Truncated to 197
HP option: ( 30+799+15*2)*0.04=34.36 again, truncated to 34
HP Option2: ( 30+799+15*2)*0.04=34.36 again, truncated to 34
1871+197+34+34=2136
Which of course, matches in-game result:
http://prntscr.com/c60af9
If we would skip this truncating operations, result would be ( 30+799+15*2)*1.31+25*2+98*2+766=2137, so you can skip it if you want to make your own calculations faster :P

On normal level char without HP and set bonuses or ML stats is easy:
Example:
Naked BK HP:858
http://prntscr.com/c5z3n2
Naked BK with ring+4%HP:858*1.04=892.32
http://prntscr.com/c5z8tx
Naked BK with ring 2 rings+4% HP: 858*1.08=926.64 (not exactly like this, but simplyfing)
http://prntscr.com/c5z9dq
(Note that the 4% is applied of base hp, not the one resulting after first ring+hp, or otherwise it would be 858*1.04*1.04=928 HP, which is not the case)
BK with an ancient set that gives +15 vit: 858+15*3=903
http://prntscr.com/c5zari
BK with an ancient set that gives +15 vit and a ring +4% HP: 858*1.04+15*3=937.32
http://prntscr.com/c5zbjv
So yeah, ancient stats are NOT affected by it, because otherwise it would be: 903*1.04=939.32 which is not the case.
Let's move to a ML char.
SM without any HP modifier except from Tree and ML Stats: 30+799+113*2+766=1821
http://prntscr.com/c5zkhx
SM with a ring+4% HP: ( 30+799+15*2)*1.04+98*2+766=1855.36
http://prntscr.com/c5zo88
So yeah, master level HP doesn't get raised by 4% option, but surprisingly (or buggedly lol) Master level HP stats doesn't either
Following the logic of the example before, if we add a 5 ancient parts +5sta: ( 30+799+15*2)*1.04+25*2+98*2+766
http://prntscr.com/c5zpmz
So if we add the last part of my gear (shield with +hp option): ( 30+799+15*2)*1.08+25*2+98*2+766=1939.72
http://prntscr.com/c5zqho
So in general, for any char formula is:
(Base HP
+ Level HP
+ Stamina Points (from stats) HP)
* HP boosters
+ HP from ancient items and options
+ HP from Master Level Stats
+ HP from Master Level HP increase
+ HP from BA/DA items
Things left for testing:
Stats from EE Bless
Vit from earth seed
%HP option from seed
Increase Max Life from ancients
My guess is that all that those will be added at the end without being multiplied (and that %HP from socket will work same way as excellent), but my gear/chars doesn't allow me to test that.
Lets now check how Life sweall(23%) works:
SM with ancient set, but no ring +hp or shield: ( 30+799+15*2)*1.23+25*2+98*2+766=2068
http://prntscr.com/c603u3
Notice that the correct way to add this HP % increase options is actually like this (But I simplified on the examples avobe because the results didn't change at all)
30+799+15*2)+25*2+98*2+766 (1871)
HP Sweal: ( 30+799+15*2)*0.23=197.57 Truncated to 197
HP option: ( 30+799+15*2)*0.04=34.36 again, truncated to 34
HP Option2: ( 30+799+15*2)*0.04=34.36 again, truncated to 34
1871+197+34+34=2136
Which of course, matches in-game result:
http://prntscr.com/c60af9
If we would skip this truncating operations, result would be ( 30+799+15*2)*1.31+25*2+98*2+766=2137, so you can skip it if you want to make your own calculations faster :P
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