Just be glad that now, they convert you right after training, or sometimes before you've even started training, so if you are going from DC-9 to...anything else, you'll start getting that higher pay rate as soon as you are converted.
The guys who followed the airplane to MEM or ATL, won't need any training, so the training planers have to work that into their timeline as well.
Back in the -bad old days- they would often train you on your 'new' airplane, then put you back onto your 'old' airplane for a month, or two, or three, then convert you! This happened to me when I got my first Capt. bid, CVG MD88, in 1992. I went through school, did my two IOE's and then they put me back in the right seat of the 757...for 3 months!
BUT...that's not the worst part of it, this is: While I was back on the 757, they realized I needed to go to RECURRENT or I'd 'expire'!! But I only needed recurrent to fly my last month on it. ie. if they had converted me one month earlier, I wouldn't need to go to 757 recurrent at all!
I called the conversion guys, and ALPA, and the CPO, but nobody would see the stupidity involved! As it worked out, I also had vacation in that third month, early in the month, and then only one more 757 trip.
So they sent me to recurrent to be 'legal' to fly ONE MORE TRIP that whole -last- month on the 757. But would they convert me 1 mo. early? NO! They didn't want to pay me MD88 Capt. pay any longer than they HAD TO!
So, I get down to ATL for recurrent, and I tell the instructor not to expect too much, since I'd just been trained on the 88! He just laughs and says, "OK, I want you to just sit over there and keep your fingers in your ears, and just put the gear up and down at the appropriate time!" He also said, "You know, if they pulled that crap on me, I think I would have called in sick for both Recurrent AND that last trip!"
I finally get converted, (on April 1, appropriate, as I felt like a fool!) and I get out to CVG (4 from the bottom on reserve) and they give me a 4 day trip on Day 1. I had alrady called the training guys and told them I wanted another IOE, since I'd been out of school and back flying the 757 for 3 months, and I even had to go to 757 recurrent.
They said, "Sorry but we are really busy right now, we just don't have anyone available for that, you'll be fine, don't worry about it..."
So then I went into the CPO to ask him for another IOE before my first trip. He said about the same thing, "Don't worry about it, you'll be fine."
I said, "OK, but if ANYTHING HAPPENS, like if I slide off a runway, when CNN shows up, I'm going to tell them I wanted more IOE, but YOU said I would be FINE!" He about choked and said, "NO, NO, don't tell them THAT!" He looked up the F/O, saw that he was very senior and had years on the 88, and said I should be ok if I just let him do all the flying! Which is what I did, but of course I bought all the beer!
Since that time they have (finally) seen the light on that and now they convert you as soon as you're in training, and you cannot go back to your old airplane for a few months while they figure it out.