I make it a point on certain days to let you know when the treasuries are moving in concert with MBS, which gives you the ability to have instantaneous access to MBS pricing, for all intents and purposes.
Conversely, I need to let you know that today, even though the 10 year is down around 25/32nds, that MBS are not even half that bad. The 5.5% is off only 8/32nds and the 6.0 is off only 6/32nds. Both are climbing in the last half hour, but have been range-bound in a 4/32nds channel (i.e. the 5.5% coupon has not been going higher than 99-12 or lower than 99-08).
Floating is safe for now. Stay alert though. If stocks tick up over 300, we could have big problems.