AmphDev just means get your current XP so say 100, then to get the “needed XP” if you want it increased by 10% over current it would be
Current XP (100) + Current XP (100) x (Desired % increase (say 10)/100)
So it becomes [100+(10010/100)]= needed XP
So [100+(100.10)]
Which is 100+10
So needed becomes: 110 XP points