I do not think the BIABacus has a specific line for altitude adjustment. My guess is that you will have to learn by experience and change the amount of hops accordingly. I know that's not real helpful, but at higher altitudes, the boiling point of wort with specific gravity above 1.000 can still be less than 100 ºC (212 ºF). It is hot enough to do what is intended.

To your exact question about hops in the boil, those added at 60 minutes (remaining boil time) will be the same for any altitude. My readings on bittering additions say that there is no good to come from boiling hops longer than 60 minutes. Aromas derived from hops are lost to vaporization at temperatures above 80 ºC and over time - mostly gone with boiling for 60 min. The line of thinking about shorter boil times (<60 min.) for hops has changed somewhat over the past few years. Recipes used to call for hops being added at various timepoints down to FlameOut (FO) and then whirlpool/hopstand additions. Lately, there are fewer hop additions between 60 min. and FO.

My interpretation of alpha acid isomerization to bitter flavor is that it occurs over time at temperatures above 75 - 80 ºC. That means that the start of chilling and the rate of chilling after FO should be considered. Once the wort is below 75 ºC, there will be negligible increase in bitterness from alpha acid isomerization. While longer time at elevated temperatures translates into less aroma, the temperatures that (post FO added) hops experience on the way to 75 ºC and down to pitching temp extract more than dry hopping alone does later. There are a lot of pressurized fermenters being sold these days - perhaps aroma hops are better evidenced in the beer if the aromas in the fermentation gases are not all escaping through the airlock. Are they really better retained in the fermenting beer if under pressure? Maybe so. I'd like to see some proof of that. Dry Hopping (DH) is done close to Final Gravity (FG) with almost no aroma being pushed out through the airlock. Note that the BIABacus has DH as a hop entry and that it gives no change to the IBUs.

There was a period when First Wort Hop (FWH) additions seemed to be common - the BIABacus does have a means for that adjustment. If you think about it, the hops experience rising temp on the way to boiling. Aromas will be lost but compounds extracted before the time at boiling may make a difference later. There was another approach that advocated for constant hop additions of small amounts every few minutes from 45 min. to FO and then even lower temps. I have not seen recipes like that lately.

Long response, yes. It might depend on the recipe and the hops involved. Altitude is just another variable among many to drive us all nuts.