There were a few who put in that amount (or certainly close) of work but only really on basic. As previously mentioned if you do a load of work on basic the learning for subsequent Area (can't speak for Aero/Approach) courses is much easier.
Equally there were others who did very little work and have sailed through reasonably easily as well. For me, I like to do loads of work so that if I happen to fail anything it's down to lack of ability/underperforming on the day rather than a lack of effort. Seems to me that if you really want to do something then a few hours study on weeknights is a small price to pay.