evaluation metrics for multiple values per session
Here is a suggestion:

Standardise everything (if you ommit this than some big number like 9999 can ruin everything), than take average value per user session. Than, optionally, mutliply this number by x/10 for example, where x is the sample size in the use session (think of it like evidence where more samples add more confidence) and finally average by number of sessions for the algorithm.