Hello @chris786,
Thank You for posting your query onto the Forum.
Well, I’ve created a combination of two-fold type of formulas to achieve the results that you’re looking for. Firstly, I created a formula to find out the MAX by each of the categories and than to calculate the correct grand totals.
Below is the screenshot provided of the results for the reference -
I’m attaching the working of the PBIX file for the reference so that you can understand and view the formulas that I’ve worked out. Also I’m providing a link below which was created by one of our expert member @Greg pertaining to the topic about “How To Fix The Incorrect Totals”.
Hoping you find this useful and meets your requirements that you’ve been looking for. 
Thanks and Warm Regards,
Harsh
Expats - Harsh.pbix (38.7 KB)