I got to the storage area and found the olde reversal process book photocopies. The process for Kodak d-94 reversal first developer is 1.5 minutes at 72 degrees F. This developer is very powerful and has hypo in it as well as sodium sulfite for silver solvants.
Home processing done at such a fast speed, with filling/emptying will surely mess up any uniformity in the process. This is a powerful developer that goes in and WHAM hits that film like a hammer and then gets out quickly. This likely results in a higher effective speed. What I think is going on here is that the developer gets in and develops the exposed stuff very quickly and aggressively--the unexposed stuff takes time to start developing fog to ruin your dmax. If you use a hotter, stronger developer, it has the effect of getting the development done before the fog can catch up. If you use a weaker developer at colder temperature for a longer time, then the fog can catch up and ruin your dmax. So to get the same dmax with a weaker development, you must sacrifice some speed.
2/3 stop ain't much.
You are going to have to live with the limitations of your processing equipment, I'm afraid.....unless you want to build a special machine. You want to go to the moon, you're not going to do it with junkyard materials...you can maybe build an airplane or balloon though.....