OK, here are some actual measurements. Open-circuit voltage with no mikes connected, 46.8 Volts. Connect one CMC 541 mike and the voltage at the unused input drops to 46.0 Volts. Connect a second CMC 541 mike and this drops another 0.8 Volts to 45.2 Volts, which is still just fine.
Add a CMC 58 (for double M/S, perhaps) and now the voltage on the unused input is 44.5, which as I've been saying is quite OK although it implies some small (ca. 200 Ohm) non-standard series resistance between the regulated supply and the phantom resistor pairs--though that low a value wouldn't give them much extra filtering of the DC or protection from inrush current, so it's hard to imagine the motive for it.
Anyway with another CMC 58 connected to the fourth input there are no more unused inputs, so if I unscrew the connector shell and measure across the terminals I get 31.2 Volts. Now 2 mA through a 6.8 kOhm resistor gives a 13.6-Volt drop while 2.5 mA gives 17 Volts. Since even the lower of the two figures doesn't quite add up to the 43.8-ish voltage I would expect, I have to suspect that the phantom resistors are lower in value than the nominal 6.8 kOhms. And potentially (no pun unintended) that could also be quite OK--the absolute tolerance is 20% as I recall, as long as the resistors are matched within each pair to within 0.4%.
So to me it still seems that as far as the microphones are concerned, this recorder's powering is a little below its own specifications. It's probably just barely OK for running four Schoeps CMC 5--s even though the supply by that point has fallen slightly below the official standard--but can the circuit put out nearly its maximum current for an indefinite length of time without risk of failure? Unless I can find out more, I'd have qualms about running this class of equipment that way on a steady basis.
I bought the $65 extra insurance policy and I suppose I could plug in four testers and leave the unit running for a week to see whether its power supply burns out or not, but if it does burn out and the insurance won't pay for a new one ... Main thing is, though, people with even higher-current microphones such as Shure KSMs, CAD Equiteks or Earthworks should continue to use outboard phantom supplies with this recorder.
--best regards