I'm actually an instructor for Allatp (ATP) - I've been instructing here for over a year and I've done a few ATP practical instruction blocks. I've done them both ways - either 2 day (4 hour) or the 10 hour program. As long as you study before you get here on all the maneuvers as well as the supplement that is supplied - you will be perfectly fine in the 2 day program. Almost all DPE's that i work with completely understand that you don't fly a Piper Seminole on a daily basis and only have 4 hours in the aircraft before a checkride. As long as you have the fundamentals and I don't have to teach you how to enter a hold or what minimums are on a precision/non approach, save your money and just do the 2 day course. Just my 2 pennies, I haven't had a single 2 day ATP fail under me yet. If you have any other questions about how it works i'd be happy to answer.