Well, as a current AYC member, and past member of their Race Committee & Scoring Committee, I'll add what I can. Disclaimer is that I have not been very active in RC or scoring for several years, so some things may have changed.
Austin Yach Club is not a time-on-distance scoring club. It has software that calculates either time-on-distance (PHRF), and time-on-time (Portsmouth), and one-design.
The software that handles Portsmouth very well. But, just like most software, garbage in, garbage out. If the race start time is not entered correctly, the elapsed time & corrected time will be wrong. If PNs are entered incorrectly, results will also be wrong.
The software at AYC does not handle different Portsmouth numbers for the same boat in the same race/series. So they just use D-PN, they do not use the wind-modified numbers. The D-PN numbers are then modified as appropriate, if the registration form has the correct information, etc.
It is very easy, and appropriate, for the competitors to ask for listing of Portsmouth numbers at, or after, the Skipper's Meeting.
The printouts of race results for each race clearly show elapsed time, corrected time, and Portsmouth number used to calculate. It also shows how many real seconds behind first place you were (cool).
There is also a regatta summary printout that only shows points/finish per race.
As for time-on-distance, and distance calculations at AYC. Race course distances are calculated using permanent buoys around which the race courses are laid out. The GPS locations of these buoys is posted on the AYC website. The projection of Windy Point into several of the race course configurations is handled by using "X" mark at Windy Point. For Turnback, and other distance races (e.g. Spring Regatta), the race course configuration goes past the locations of AYC's permanent marks. Distances are calculated using waypoints located along the rhumbline of the course, even though the waypoints may not be actual marks of the course. Course distance is always calculated along a line that goes over water.
