Oh well, thanks for your comments and bumping the thread, although most of the comments pertain to something else than the issue that makes me cry with 15k silkweed and mushrooms in storage currently.
I can confirm the following for the Alchemist's Flask [item=75525]:
without flask = INT @ 90lvl = 15934 (char1) *** 19669 (char2)
with flask = INT @ 90lvl = 16287 (char1) *** 20022 (char2)
difference = 353 *** 353 (without mixology 320)
difference % = 10.3125
And the following for the Flask of the Warm Sun [spell=114771]:
without flask = INT @ 90lvl = 19669
with flask = INT @ 90lvl 20772
difference = 1103 (out of 1000)
difference % = 10.3
Oh well, it was working 2 weeks ago, right after the fix was implemented. I did the same calculation back then.
Now, it seems not to be working properly again.
HOWEVER, WE CRUCIALLY NEED TO HAVE THE FOLLOWING FIXED, WHICH IS WHAT I MEANT INITIALLY:
https://www.warmane.com/bugtracker/report/476
https://www.warmane.com/bugtracker/report/610
https://www.warmane.com/bugtracker/report/5558
/sad panda