Replying to I need help with a tricky math question

I'll provide context later, but this is the problem we are trying to solve and having a bit of difficulty figuring out. The numbers are just examples, but the context should be the same:

In Q1, our results were +20%. In Q1 we spent $10,000 to get our result of +20%, at a price per percentage unit of $500 per % unit.

In Q2, our results were at -8%. This time in Q2 we spent $8,000 to get our result of -8%, but if we follow the same procedure to determine our price per percentage unit we would get -$10,000, which is incorrect. We are spending more money, but the outcomes this quarter are worse.

How do we calculate the cost per percentage unit in this case?/