MA FF seatbelt install issues in an Odyssey

[HIU8]

Last week I had installed 2 MA outboard and FF in the third row of our Odyssey b/c DN was with us. After posting here I finally got the install solid using the seatblet. However, no matter what I did, or how many times I reinstalled, the seat would come forward and then retract when I was tightening the harness. Is this normal? I'm very bothered by this knowing that when DS hits 40 lbs I have to use the seatbelt. I'm so used to the LATCH install which I can get rock solid every time and when tightening the harness the seat does not move. Is this a problem other's have had? How do I remedy it?

Thanks

[DrSally]

I'd like to know too, since I'll eventually have to do the same thing in my Oddy. My brothers Dodge Durango doesn't even have latch and I had a heck of a time installing a seat in his car.