Firstly, credits to cpa4989 for bringing this situation up. I tested this situation with the Essene Poyo with Mindbuster (non-crits only). Tested this with 4 situations (wearing same gears throughout, except when mentioned otherwise). Blue Spritz, Dragon, and Priest Pearl all offer +15 INT (and I chose Def Spritz and MP Dragon to avoid Magic % being involved in testing).
# | No Mount | Blue Spritz (Def) | Blue Spritz (Def) + Priest Pearl | Dragon (MP) |
---|---|---|---|---|
1 | 1582 | 1593 | 1652 | 1629 |
2 | 1583 | 1587 | 1640 | 1656 |
3 | 1571 | 1563 | 1645 | 1626 |
4 | 1573 | 1591 | 1636 | 1635 |
5 | 1570 | 1577 | 1636 | 1627 |
6 | 1578 | 1579 | 1646 | 1652 |
7 | 1583 | 1568 | 1658 | 1654 |
8 | 1580 | 1572 | 1632 | 1626 |
9 | 1571 | 1590 | 1626 | 1656 |
10 | 1581 | 1575 | 1634 | 1645 |
AVERAGE: | 1577.2 | 1579.5 | 1640.5 | 1640.6 |
Even with the small sample size of 10 non-crit Mindbusters, the differences are obvious above. So as clearly seen, the +15 INT from the Blue Spritz isn't truly applied (same damage as if you had no mount).