Sage payroll training in 3 days - to good to be true?

Hi after completing Sage Accounts Level 2 I was hoping to train for sage payroll. Unfortunately no colleges seem to be covering a night class on this. When I goggled it for courses running I have found a place advertising sage payroll intro training is 2 days 9.30am -4.30pm and a further day for the payroll advanced again starting at 9.30 and finishing at 4.30. It will cost me about �500 to complete the two courses and my question is how on earth can I cover everything i need to know in just 3 days? I had seen it last year in my local college running from Feb - June but the course was cancelled because of low numbers. This was giving students 5months to complete course and sit the exam. Does anyone have experience in sage payroll training over such a short space of time? Any help would be very much appreciated, as I'm hoping to join a family business and having the knowledge of payroll would be a great help. Thanks!!