I guess the question I'd ask the OP is, if FL75 isn't the minimum altitude at DIXIR (and I agree it is not unless on the STAR), then what IS the minimum altitude? What altitude would you be prepared to descend to prior to DIXIR and where are you finding that information?
To me, the Jepp provides a few numbers, FL75 on the XOLSI - DIXIR track, 7100 in the grid, and 4700 in the sector just as you get to DIXIR. None of these numbers are 4100. You don't get 4100 until past DIXIR. I think it's confusing and I'd be asking questions of ATC if it was me.
Questions for ATC, "Descend via what procedure?"
If the answer is "The ILS", then I'd be asking what altitude do you want before we get to the ILS.