Disadvantage when selling unused token

Unknown

If you sell an unused cover you get Iso 8. If you upgrade your token with more than one cover and you sell it, you're put in a disadvantage.

For example:
You get the first Cover of Black Widow (Modern). Now you could sell it for an amount of 100 Iso 8. If you get a second Cover and you use it, you could upgrade Black Widow's abilities. Now she had Aggressive Recon Level 1 and Widow's Sting Level 1.

If you sell Black Widow now you will also get 100 Iso 8 instead of 200 Iso 8 (for 2 Cover).
If you level up Black Widow (not her abilities) you will get more Iso 8, but not nearly the amount, you spend.

That's not fair!

I think, you should get at least the amount, you will get for the single Cover. If Black Widow's Aggressive Recon and Widow's Sting are both on Level 5 you should get at least 1000 Iso 8 (the amount of 10 Cover).