Find a value associated with a name and nearest date and calculate a projected value

Hi all, in the attached sheet you'll see what I want to do and how I've gone about it - but what I'm thinking is there might be a better (and quicker) way than what I've done.

Here's a screenshot:

sample.JPG

Basically I want it to take the 'match date' and then find the personal bests recorded for the player before and after this date and return a 'virtual' personal best ('PB on match day') by calculating the 'change per day' (CPD).

What I've got works, but I imagine it's going to be clunky when I put it all in one, and with tens of thousands of these calculations to do the quicker the better.

Here's the spreadsheet:

https://docs.google.com/spreadsheets...it?usp=sharing

Thanks for looking!