I bought all the helicopters with the money glitch mod thing. Why not buy it? Let me put it this way.. the places the helicopters you order spawn (attack helicopters), they will spawn by mavericks, froggers, and all other non attack helicopters. You have a bounty on your head and you need to a buzzard. Why? I don't know you just NEED one. So, you travel from simeon's garage with a trail of angry money hungry whores trying to kill you because you collected a high end vechile and because you have a bounty. The buzzard says it's spawned at the airport. Okay? You go to the airport and a frogger is there. f*ck! You order it again and it spawns at the sandyshores airfield. You finally make it there with a inch of life and it's not there because a private jet, titan, or maverick is there. f*ckING PEGASUS! Your last attempt. You order it AGAIN and it spawns further up at the merryweather airfield. You finally make it there and with one more bullet, you're dead. You're about to survive your bounty and as soon as you get there, a maverick, frogger, the little stunt planes, cargobob and everything EXCEPT your buzzard is there. Okay. You finally say "f*ck it" and go for the cargobob. As you're getting in the cargobob, a rocket comes flying your way and blows up the helicopters and planes, stripping you of your bounty and leaving you with a bunch of people spawn killing you.
My point is, most of the time, when you order a helicopter, the ones that will always be there are the maverick, frogger, or others. If you order one of them, you have a very high chance of it not being moved by Pegasus. If you order a attack helicopter or something else that will spawn in the same place, the chances are more little. Always go for the non-attack helicopters when trying to fly away and only go for the attack helicopter when you're planning to kill someone.