My Neptune 7500 also offers a warm/warm wash/rinse temp selection. Moreover, if you select the "stain cycle", then the first rinse will be the same temp as the wash. This means that you can have a hot wash followed by a hot rinse - something NO other modern consumer machine seems to do (unless it's hidden in a pre-selection). I routinely use this option when using soap and STPP instead of detergent.
Additionally, I've noticed that the "warm rinse" option, at least on the 7500, is really a "tempered cold" rinse, in that it regulates at 80F, not the 105F of a warm wash. I'm assuming most modern washers' "warm rinse" isn't truly warm but rather a lukewarm setting also. Yet another reason to use the stain cycle.
What else the stain cycle does is insert pauses between each tumble pattern, effectively lengthening the wash cycle by about 50%. This is why if I would normally select a 16 minute wash, with stain cycle I'll select a 10 minute wash, and the wash time will still be about 16 minutes. Thus I can get a true warm or hot first rinse without the cycle taking any longer than normal.
BTW, I'm still experiencing very nice results with the Ivory soap/STPP combination. I haven't found any need for fabric softener or even vinegar. Towels come out more fluffy and absorbant. Sheets come out both crisp and smooth/soft, esp when line-dried. Dark colors seem to look better, also, freed of the nearly ubiquitous optical brightener fluorescent dye conundrum. No sign of graying of whites, either.