Hi,
What did ATT Tech Support say, especially since you are paying top-tier price?
On another note, my question about 1 or 2 pieces relates to a change I made to my system that I don't believe can be made to yours but I'll check it out. It made a HUGE difference to mine, huge meaning going from around 20 mbps max download to 108 mbps max download. I pay for the minimum tier because testing over the years only gave me minimum regardless of the tier; I did one month tests of each tier.
I'm curious to hear what your Support people told you!
P
P.S. It just came to mind that fiber does have some constraints, like bends in the cables, etc. since it's light through glass. Also, used to be that it required an additional interface (a big stumbling block to students at the university I taught/worked at circa 2000) but I doubt that is the case today....