Cap on the amount of remaining aps

A little introduction here. Skip the first spoiler if you don't have time to read it fully.

 Spoiler

Since Nexon implemented a level 10 minimum limit to join a family, rep mules have been almost impossible to make. However, with the new life cash item, I wanted to try a new idea for rep mules. The idea was to start with a lvl 30 char, to leech it using my mains and to collect reps on my other mules.

That's basically what I tried yesterday. I had a lvl 30 char and leeched as much as I could in a day to see how much rep I could gather. I managed to get to lvl 83 and I did not do 3rd job advancement. This is where I noticed something was wrong.

So I was lvl 83. At that lvl, one should have 5*82+25 = 435 total aps. Here is an ss of my char:


There are a few things wrong with this ss.

1. It is missing 10 aps. I did not bother adding aps since lvl 30 because I was leeching. I remember that at lvl 81 I also had 255 aps remaining. This would mean that on my last 2 lvl ups, aps have not been registered. An alternative would be that the 10 aps went in mp, which seems very unlikely to me. Is it possible that aps gained once I had 255 aps remaining are lost?

2. I am able to take out from hp/mp. Obviously, as a rep mule, I did not add any point into this pool. How is it possible that I can reset now?

I am conscious that my ss is not an absolute proof, as I could have added 10 aps in mp. I did not know about this cap so was not prepared to have good ss. Anyone is welcome to test this on another char. If you don't believe me, I can't convince you more unless someone else makes another char like this.

Also, I tried adding aps to str. It went down to 254 on the first click, so it's not hidden aps.

My question: is there any way to confirm there is indeed a limit of 255 ap remaining? More specifically, should I try buying 9 more ap resets if I continue this char?

edit: I know 255 is 2^8-1.