It no longer permits the purchase of additional segments above the four (six in N.A.) per continent. Or maybe this happened even earlier but I missed it then?

I use ExpertFlyer. Enter the same airport code for origination, destination, and purchasing location. If desired, can also enter A, D, or L as booking code.

Still have to do a separate query origin by origin. There was some discussion a few years back about making the comparison spreadsheet available to EF subscribers, which would both make things easier for people to compare fares, continents, classes, and origins, and also reduce EF's costs since subscribers would access the spreadsheet rather than making multiple queries. But nothing came of it.