Ernie,
Thanks very much for the reply. I forgot to mention that I tried the +\- keys as well. Anyhow, I guess it was just wishful thinking that I could have "at or..." restrictions. It's not a big deal though. Also, I'm fully aware of how speed can affect the decent rate (-2000fpm @ 60kts is more steep than -2000fpm @ 600kts). Here's the problem, If I turn off VNav and adjust the decent rate manually, using the Boeing style ND as a guide (i.e. the "semi-circle decent marker thing"

) I can get to the desired waypoint a little before, thus being sure that I've made it at or below...BUT the problem is I can't get VNav to turn back on successfully.
NOTE: I flew last night after writing my first posts, and I couldn't get this to happen every time. I tried a few time during cruise and it only happened to me once. Then I tried once during decent on a STAR and it happened. Also, when I trned VNav on and off, I didn't delay; once it was off, I turned it right back on again, and [sometimes] it went right to destination altitude.
I bought the FMS pack about a month ago, so I'm not sure which version I have, but in the ISG folder within FSX I have "readmes" for patch_1, patch_2, and Upgrade_1_4. So I'm assuming I have 1.4.
Anyway, thanks very, very much for the help, and I'll be sending you my info.