That doesn't make much sense since we are rarely currently logging time under the Part that we will be applying for in the future.

I'm sure there is a FAA legal interpretation about this. Call your FSDO and ask them for their interpretation. It makes sense to me, but again, I'm no expert.

To simplify, I need to log a landing if I want to count all those point-to-points (under 50nm) toward Part 135 XC minimums, right?

Thanks Gjn290. I realize that I was unclear in my original post. I wouldn't be currently logging 135 XC time, I'm logging time toward Part 135 minimums, which is different. Either way, the question remains. I think it seems safest to log a landing in order to avoid any sideways glances/uncomfortable explanations @ the interview.

Cross country time is logged per whatever your applicable category is (61/141 or 91).

With regards to landings, the usual rule that I've seen followed is if the CFI is "guiding" the controls and assisting the student in inputs, the CFI logs the landing since they were manipulating the controls (they were not the only or main manipulator though, if they were, no question) or if the CFI assists on all landings, they sometimes split the total # of landings (usually in a 70/30 manner for the student). Likewise, if the CFI is sitting there because your student is fully competent enough to land on his/her own with no guidance, then the landing goes to the student.

61.51 is clear about everything except landings.