Sum values in range of text strings based on other values

[afgoody]

Hello,
In the attached file, I'd like to be able to total the numeric values that preceed certain alpha values in text strings. For example, Item #1 includes "5P" while Item #4 includes "1P", so B6 would be 6. I've played with search and mid, but can't figure out how to iterate through multiple rows and keep a running total (without VB).

Thanks,
Adam