Hi Robert and welcome,
Sounds like you’re ready to go which is great. Your 40 vs 100 hr questions is one that comes up fairly often. First off a little background, you see before 2013 there was no 1500 hr requirement to fly for an airline. You only needed your Commercial license and most Regionals only required 5-700 hrs and 100 ME (multi). ATP only offered the 100 hr Program to ensure that you met that 100 hr minimum. After they implemented the 1500 hr Rule pilots now found themselves instructing for 1-2 yrs vs months. Those pilots that instructed for ATP found themselves with hundreds of hours of ME time and far exceeded the requirement. Based on that ATP determined they could offer a lower cost option for those pilots who would definitely be instructing for ATP. If you wouldn’t be for any reason (instructing elsewhere, flying SE cargo, banner tow etc) they still have the 100hr course to meet the mins. Now to be honest If they offered the 40 hr Program back when I did my training I pretty certain I would have grabbed it. BUT, having gone through the 100hr Program myself I def feel there are some benefits (all things being equal). The following is from a post I wrote a while ago:
Proficiency: Most people are obviously very anxious to jump into training, flight instruct and get hired. For most of us it’s the means to an end. BUT glossing over that flight instructing part is easier said than done. The first time you find yourself sitting next to a student who knows NOTHING and seemingly for some reason is hell bent on trying to kill you both can be rather daunting. Now there’s a fun fact most non-pilots don’t know, more people have REALLY BAD DAYS flying in an twin engine airplane that loses one engine then people flying in a single who lose their ONLY engine. Now this should sound odd to you since in a single you’re now a glider pilot. The reality is when a twin loses one of it’s engine’s some funky stuff happens initially which needs to be addressed quickly and if it isn’t bad things happen (this btw is the focus of your multi-engine training). The first time I found myself doing a Vmc demo (THE scary maneuver?) with a new student I was very happy I’d done the majority of my training in the twin. I’m not saying this to alarm you or convince you to drop another $10k. Nor am I saying you won’t be skilled, trained or prepared with 40 hrs. What I am saying is more experience is never a bad thing.
Longer Cross-countries: This was actually one of the factors that attracted me to ATP in the first place. At ATP you’ll earn your Private and then your Multi and Instrument ratings. Next comes your Commercial license but there’s a problem, you won’t have the 250hrs you need for it. So what ATP does is they pair you up with another pilot and send you flying for 2-3 weeks to build that time. Pretty cool. Now if you’re going for the 100hrs you’ll be building that time in the twin and that means, due to it’s longer range and greater speed, they’ll send you farther, potentially much farther. I did my training in Virginia but my cross-countries took me south to Florida, west to Texas and north to Chicago! Now you may be thinking that’s cool but I’m not spending more money so I can sight see. It’s not about the distance or the locations, it’s about the flight conditions you encounter. I crossed the Appalachians (mountainous terrain) going west, dodged monster thunderstorms going south and picked up some nasty ice going north. When all was said and done I finished with a tremendous amount of confidence in my knowledge and abilities. I really was a pilot!
Now of course all things aren’t equal and $10k is a lot of money. I’m just saying if money weren’t an issue, I do believe that’s the way to go.
The only difference between the SE and ME Instrument rating is when you do the ME you’re required to do a SE (Engine out) approach on the checkride. So if you got your IR in the twin you’re good, If however you get it in the single, when you go for your ME checkride, you’ve got to do a SE approach on that checkride. Make sense?