if your last education was not 4.5 years old...you definitely fall in SPP...however if it exceeds 4.5 years, yet you have work experience, some colleges will still consider you under SPP. 10 year B1/b2 visa required permission every time u wish to visit USA now. however, as u retuned earlier, hence getting another permission of visit won't be a problem for u. and your visit to USA will certianly be a plus for u when u apply for canada visa.
Cheers!
Cheers!