Filing complete when Checks Cashed?


My employer was a bit skeptical about filing the petition because it was almost over. How long does it take for the checks to be cashed generally?? say my docs were received by USCIS, how long will it take for them to cash it? Does it mean you are in ONLY when your checks are cashed or when USPS notifies that the docs were delivered?? which counts?

In case of PP cases, they are cashed within 15 days. However, in case of regular processing, it can take few weeks (or may be months).