Bi-wiring using both speaker 1 and 2 outputs

I have a McIntosh MA6450 integrated amp. The amp supports two pairs of speakers and allows both pairs to be on at the same time. Currently, I am using this feature for bi-wiring purpose. That is, I connect one pair of cables from "speaker 1" to the low-frequency posts and another pair of cables from "speaker 2" to the hi-frequency posts. It works fine. Are there any protential problems with this kind of wiring?
Does the manual state the minimum impedence for speakers played at the same time? I suspect that the impedences will be missmatched for the high and lows and the power transfer not ideal. I would hook up both wires to the one output to be sure.
relax I believe that this arrangement is just fine. As long as it sounds good, I wouldn't be concerned at all. The speaker switch just connects one or the other or both output connectors internally to the amp's output. If you want to prove this to yourself, set the speaker switch to "both" get a cheap ohmmeter from RatShack & ohm between the two [+] posts, also between the two [-] posts (AC power off & speakers disconnected). You should read very close to zero ohms. If you do then all is well. But I wouldn't even bother with that.
I do the same thing with my Arcam A32. In fact, it is one of the options described on the manual.
Thanks for the info. It's good to know that I am not along doing this. I had some difficulties inserting 2 12awg bare wires into the same speaker connector, that's why I use this scheme. BTW, the McIntosh MA6450 works *very well* with my Tannoy Definition D500; tight bass and the 3-D sound stage is incredible. I listen to music for a long time while grading exam papers and never feel tired. Thanks.