Crossing legs effects BP?

Hello everyone! Just thought I'd pick your brains for a minute... (my apologies if this is posted in the wrong section)

I was at my family dr. recently for a follow-up and the MA who took my vitals instructed me to uncross my legs before she took my BP. So here's my question, does crossing your legs actually have a measurable effect on BP?

I could understand uncrossing my legs if we were doing dopplers to evaluate blood flow to lower extremities, but this was just your typical run-of-the-mill follow-up appointment which had nothing to do with my BP anyway!

Also, just because I thought it was funny; my BP was 90's/40's. The MA was incredibly concerned about my 'low BP' and nearly ran for the dr. until I told her I typically run this 'low'.
90/40 is pretty low in my opinion.. and of course crossing your legs affects BP. Learned that first few weeks in nursing school We are told to have the patient sit with feet flat on the floor for a few minutes before taking BP. No one does that of course

I run that low (sometimes lower) and it's funny to see the reactions of the MAs. I had one ask me how I wasn't passed out in the floor. lol I'm little! I don't need it to be higher. Celebrate your BP!

Some of us just have low blood pressure. My lowest measured BP was 56/"not quite sure" (nurse's words, not mine!). When I'm not overweight, my "normal" is typically in the 80s or maybe 90s systolic. And yeah, I pass out if I stand up too quickly!