Formula for costing units

I hope that I am posting this in the right area.

I am currently building a game and looking for a formula to cost my units. The game puts units in combat with each other, using their statistics, which are as following.

Skill, Attack, Wounds.

Each unit has one attack and one wound. The combat system is based of d10s.

Unit 0 has a skill of 1

Unit 1 has a skill of 1

Unit 2 has a skill of 2

Unit 3 has a skill of 3

Unit 4 has a skill of 4

Unit 5 has a skill of 5

If the Skill values of the units are the same then they will hit each other 50% of the time. As the difference grows then the amount of time they hit each other changes to reflect this by 10%.

For example

Unit 0 will hit Unit 1 50% of the time (6+ on a d10 with the 0 counting as 10), Unit 2 40% of the time (7+), Unit 3 30% of the time (8+) unit 4 20% of the time (9+) and unit 5 10% of the time (10+)

Unit 5 will hit unit 4 60% of the time (5+), unit 3 70% (4+), unit 2 80% (3+), Unit 1 and unit 0 90% (2+)

What I want to work out is whether or not there is a formula for costing these units so that they are balanced in cost compared to what they do in order to balance the game.

I had thought that if you had something like

f(n)=f(1)*(1.5^n) because unit 2 is 50% better than unit 1 and unit 3 is 50% better than unit 2 and so on. I am wondering if this will work?

I thank you greatly for any help.