O-1 vs. O-1E requirements

What is the time in grade that they gave you? TIS does not count towards promotion only for the pay scale. There is also a difference with housing also.

Nine months TIG; 5 years, 10 months, 8 days TIS. I'll make 1st Lt much faster and be eligible for captain sooner as well. And I'm not an E because part of the TIS is converted IRR time. (Since they do that, I don't get why the 'E' is relevant anyway - credit folks for their TIS regardless of how many days they have and pay them accordingly. The E means nothing for promotion or anything else other than pay. You can't look at a Lt with an O1E designation who's my age or myself without it and tell the difference unless you ask.)

The pay computation they gave me of course counts BAH.

The difference in housing, to me, is more significant than the difference in pay because the housing is actually/technically worth about 25 to 30% more in the first place since it isn't taxed. By the time the Feds and the state (if your HOR requires you to pay income tax) get their cut, you've lost most of it anyway.

At any rate, the OP should definitely speak to a HP recruiter.

That is right IRR time does not count towards the "E" since you do not earn any points for being in the IRR. Sounds like you had less then 4 years or 1460 points of active duty enlisted. The housing difference does add up over time and as you move up in grade and the pay difference as you move up in years on the payscale. OP needs to speak with their recruiter since things are easier done before you sign then after.