I agree with all of that, I just think both options equally meet those objective criteria. The only difference is how the recipient perceives the message. I t

I agree with all of that, I just think both options equally meet those objective criteria. The only difference is how the recipient perceives the message. I think it's largely a difference in culture between academia (my realm) and business. A professor, for example, might assume that you have particular reasons for selecting the time slot you have and wonder whether he should clear room in his schedule to meet your expectations. In this case, selecting an exact time before hand provides a minor inconvenience to him.