Question about my Hartke head, ohm loads...

I have a Hartke HA 5000 head. It says it's two seperate power amps, one for highs and one for lows. They each put out 250 watts at 4 ohms, or 170 watts at 8 ohms.

Now, you can defeat the bi-amp crossover circuitry with a switch. The manual says that when you do that, both amps work in full range.

My question is this-

Are the two power amps really totally seperate? Meaning, can I run a 4 ohm cab off amp A, and a 4 ohm cab off amp B, giving me 500 total watts of full range output? The manual does not address this exactly. I don't want to end up with a 2 ohm load and kill my amp. But it seems to me, if these really are two discreet power amps that run 250 each at 4 ohms, that that figure should apply to both amps. Meaning, I can run two 4 ohm cabs for 500 watts, as long as I don't try to run both off the same set of outputs right? Right?

Your read, is how I read that. I threw another idea into your cab thread. Basically think about 'splitting' a cab so that it can take advantage of both sides of the head full range. If it sounds complicated - it isn't ...

The two amps are seperate 250W Per Channel.Top outputs for one amp-bottom pair for the other.The two amps are not bridgeable.
Used a Peavey Megabass,same configuration for many years,nice setup.