Why pay them the whole sum up front? Screw that! If they really want your business they'll work something out with you. I noticed their "fleet" had a couple Seneca IIs and an Aztec... wonder if those are part of the time building package? I doubt it. A "network" of Senecas... is the company like a broker or something?
What kind of quality are they giving you? You and another dude log PIC, in the same aircraft at the same time. Sure it can be done, but really?
I would be a little skeptical.