I just check it without easy rpg and no easy rpg is not affecting the upgrade system because i still cant get all of rank 1 skills even though i have 1800 spirit points i should of gotten all 3 of rank 1 skills.
There should be an instruction book that says how the upgrade system works like the red book in the beginning that tells you how medicine and adrenaline works because i just assumed that you could of obtained all of them at once.