I've calculated the number based on your screenshots myself as well as inquired to them. I guess I'll begin with their "opening" number is not 375,000, rather 330,000, because one of the bet is actually losing before they got cancelled, I guess it's not shown on the images you provided. So, 330,000 USD, 330,258.69 to be precise.

From this number as our opening number, if we're going for half, it'll be 165,129 USD, and you've got 119,750 from the stake returned. Plus extra 5,000 USD bonus that I don't think mentioned anywhere [feel free to confirm or deny]. Using the "opening" number they proposed, halfed as a gesture that both sides willing to meet in the middle, and substracted by what's returned to you:

USD 330,258.69/2 = 165,129
USD 165,129 - 119,750 - 5,000 = USD 40,379

If you're agree to that number?