What is this plug circled? Is this another fill plug???

[blaubenz]

The first pic is what my 2005 x5 4.4 tranny look like from the right side looking a little forward. Notice there there is a "plug" on the right side with a black dot on it. Conventional wisdom said, I can not put an allen wrench in there to use it as a fill plug instead the fill plug is in the pan, recessed upward to fill see pic 2 that follows.

My question is what is the screw I circled? Is that another filled plug? Does anyone know what that screw is for?

I attached another tranny that have a similar screw picture 3.

Note: The reason I asked is that ever since I changed my tranny oil I been look for a way to add more tranny back into the tranny. I took out about a quart more than what I was able to put back in (Believe me I did the proper oil fill procedure and other combination to try to get more oil in). I suspect that I have low tranny oil because I have hard shift when cold particular from 1 to 2.