Having designed courses for the USA championship several times now, I've come to realize that the number of foxes to find doesn't tell the full story. Here, of course, we've got longer courses overall for M40 competitors, so even finding all five foxes the shorter M50 courses will probably not be as demanding physically. But even when two age/gender categories are out on the same course, and are required to find the same number of foxes, the length and difficulty levels can be quite different between the two. Not only might one fox be located a much greater distance away making one category's course longer, the course layout for one might be much trickier to navigate due to terrain, elevation, propagation (on 2m), or just the difficulty involved in determining the correct order.
With more transmitter combination possibilities provided by sprint and foxoring, the total number of foxes can be even less indicative of overall course difficulty. But those sprint numbers are surprising to me. It will be interesting to see the courses. Perhaps they will reveal the reason for the small fox totals for those categories.