OK, sorry for not watching the video, but I prefer text-only (besides the pain of watching a youtube video over a crappy proxy at work.. makes you wish they would just block it

Can you "prove" that your N900 is actually going down to 125Mhz? (with conky or, better, by ssh'ing into your N900 from a PC?).

I mean, it could be that you don't have a problem after all. In theory the phone will not enter the frequencies which are listed as avoided, so what you have in the minimum is, in your case, irrelevant.

In any case, it may be that the phone app actually requires (by design) to jump back to 125/250 (whatever is available), so you might want to set your minimum limit to 250Mhz (as I have), and see if that's OK with you.