That is how I always wear my seatbelt. I am very short and, um, anyway, it is very uncomfortable to wear it across my shoulder and downward. I am wearing the stupid thing, that is what the law said, I thought. Hope this woman fghts the ticket and wins. Doubtful, but I can hope.
I understand the problem, it is not one size fits all. My hope is that you are safe in your automobile. I think seatbelts are a benefit most of the time, but one time I took mine off to get out my wallet for a traffic stop and the cop said he was going to give me a break but I should wear my seatbelt. I calmly explained that I took it off first, that I took out my wallet to give him my driver's license when he walked up.
Bottom line, in a non-accident situation, keep your belt on until they see it. Aye carumba. I've been wearing seatbelts religiously since I was 15-1/2 (driver's ed films made a believer out of me).
Do you know that in most later model cars the upper anchor point of the shoulder strap is adjustable?