I second this opinion, although (as a retired LTC), I'm a little ticked that a personal appearance promotion board would expect this of you or anyone else. Maybe your 1SG could have a little talk with the company commander about making that trip up with a little "RST" (As a former Company Commander (USAR), it's what I'd have done). In either case, the extra pay that comes with the promotion will make it up in short time. Congrats for showing some initiative!