Winds Aloft Overlay on AOPA Internet Flight Planner

Perhaps may of you have already used the AOPA's Internet Flight
Planner. I'm assuming that the software is powered by Jeppesen's
Internet Flight Planner. I have noticed that you can overlay the
winds aloft on the chart. It looks to me that the winds aloft
information presented on this program is much more detailed than the
winds aloft available from www.aviationweather.gov. For example, you
have a lot more winds aloft stations than the aviationweather.gov on
the map. It also looks to me that the winds aloft can be attained in
the increment of less than 3000ft, which is not possible in
aviationweather.gov. Does anybody know where this software is getting
this winds aloft data from? How reliable is this? -- i.e.) winds
aloft at 7500ft and 8000ft are indicated slightly different.

I was looking at the help file on the AOPA's Internet Flight Planner,
but no further information was provided. I am curious to see if there
are many other winds aloft stations than just the ones available at
aviationweather.gov.