Rules vary somewhat from state to state regarding who has to sign off on what. However, all states whose rules I have reviewed do allow experience from multiple employers. So, I completed 11 months of my experience at 1 employer and the last 1 month at another employer. In my state, the manager doesn't have to sign up, but any CPA who is familiar with your work, so neither of my managers signed off on the work as neither was a CPA, but a CPA who was familiar with my work at both places signed off on both experience attestation forms. Most states require it to be a manager who is a CPA; if you are in one of those states, both (or all, if more than 2 jobs) managers would need to sign off.
While I'm not aware of any states that have an experience tracking module where you can verify your experience as you go, they do all have ways to verify your submitted information if they have reason to doubt it. As one example, quarterly unemployment filings in KY require that employers list each employee's social security number, name, number of weeks they worked in that quarter, and total earnings in that quarter. So, if the KY state board had reason to doubt an applicant's information, they may very well be able to contact the unemployment office and say “Do you have record of Jane Doe working at Smith & Brown for 52 weeks?” and if unemployment says “We don't have nearly that many weeks reported”, then Jane Doe is in trouble. I'm not sure what sources of information are available in the level of background check that the CPA board is able to do, but I wouldn't be at all surprised if they are able to confirm – beyond just asking a manager – how long the duration of employment was.
So, I don't think they track it routinely (like in a way that you can check to see if their totals match yours to make sure you're on track), but I think they can double-check to see if questionable information is legitimate or not.
.