Solved

Overfill Development?

Can you overfill development points? I topped my acceleration which ten reached 200 but I was able to add a few more remaining points. Did I lose these or does it continue to add them on even though it still says 200?

So the software doesn't prevent you wasting points? 

It doesn't, because you could put 200 points on say, acceleration, and then change suppliers so your point aren't wasted.

This just isn't really worth it, however, since the points you get from the supplier are points you could have just spent yourself, without the fee of buying a different supplier as well.

No entirely correct.  Once you have maxed out say Acceleration and you change suppliers the extra pts you receive are just that extra(you can’t spend pts you haven’t got) and in Elite is impossible to max every category especially since FE and TE more important now than there were before.  Most mangers will adjust suppliers to ensure they are always getting the benefit of these extra pts.