Can any of you help with my trip planning with estimates of travel speeds that people manage when in Mongolia?

I've heard wildly varying figures which are probably due to downtime eg local tourism and relaxation, breakdowns, etc. and how much actual riding was done in a day. The guys here seemed to average a huge 580 km/day by my calculations: Mongoolia 2005 -www.moposivut.com-. I doubt this is realistically or regularly achievable given the LWR guys getting so much less with a LOT of effort. (Yes I know what you all think of them, but it does provide an indication of how much it can vary). It's so hard to get info on how far people have gone in a day, and what they mean by a "day". 4 hours riding? 14 hours riding?

Knowing this stuff can really help with the eternal struggle of balancing a schedule that's not too hectic while still being able to cover lots of ground and see more of the country.

So what would be a good figure to use for trip planning then, if you took all these variables out as best you can? How far could you reasonably expect to travel in an hour, or in, say, a day with 8 hours of riding? Are there any areas in Mongolia where you'd allow a lot more (eg around UB) or a lot less (eg in the Gobi or in the mountains)?

Thanks in advance!