User blog:Roboteer-beginner/Robot\Alt upgrading formula

During non-episode days in summer I'm going to create as many TL formulas as I can.

Today I want to create characters upgrading formula. As I'm not sure if it is the same upgrading trans-scanned characters, I'm going to find out only upgrading with cards not durind episodes not-TS characters formula 

First of all, upgrading R4 card-Episode Decepticon Rumble

1)Level 1, upgrading with 10 cards=>Level 12

Stats changes:

Atack: 2891=>3737; that is 29,26% increasing, or 2,66% per level

Health: 7616=>8786; that is 15,36% increasing, or 1,4% per level

Defense:449=>781; that is 73,94% increasing, or 6,72% by level

That doesn't look good... What about absolute values:

Attack:+846 (+76,91 per level)

Health:+1170 (+106,36 per level)

Defense:+332 (30,18 per level)

It looks like several levels upgrading isn't good for creating a formula

2)Level 12, upgrading with 3 cards=>Level 13

Stats changes:

Attack: 3737=>3807 (+70)

Health: 8786=>8895 (+109)

Defense: 781=>807 (+26)

That results aren't equal to the first ones, so continue upgrading

3)Level 13, upgrading with 1 card=>Level 14

Attack: 3807=>3878 (+71)

Health: 8895=>9006 (+111)

Defense: 807=>833 (+26)

As changes are increasing, a formula shouldn't be based on basic stats, so continue upgrading: