I think just about every service software tracks labor costs.
I've only seen broad averaging for chemical use, and that's typically based on purchases v. cleaned area over a months/years period.
Accuracy would require data input on the part of the tech that might not be all that accurate or even counter to job efficiency. Of course, you could just tell them that chemical costs are such a tiny part of the work that it really isn't worth the effort to be that finicky.