Is SOC in Hold SOC setting relative to start SOC?

If I have the i3 parked for the night at 60% SOC and start with the same SOC the next day morning, could a coded REX be turned on immediately or only after waiting for the SOC to come down to 75% of 60% SOC?

I have seen descriptions where it's mentioned that anytime the car is stopped and restarted, Hold SOC can only be manually activated after the battery has depleted to 75% of the START SOC (NOT the TOTAL SOC). I have seen tips like keeping the driver belt buckled before the driver door being opened to make sure the i3 (or REX?) continues to run.

Also, I am wondering if the REX continues to run once manually activated to hold SOC until it reaches 100% SOC or if it stops as soon as the SOC it's set at (say 70%) is reached.

Thanks in advance.

It's 75% of maximum, not 75% of "when turned on." You'll be fine. (At least, it's let me turn it on immediately after turning on the car when at <75%.)

As for "charge level", it charges up to whatever you set it at when you pushed the button. So if you set it at 60%, it will charge up to 60% then stop. (Obviously start up again should you drop it below 60% again.)

As an example, if you're driving up a steep hill on the freeway, and press Hold SOC at 60%, then stop at a rest area at the top of the hill with the battery at 55% (because REx couldn't keep up,) and sit with the car in "on" mode in the rest area, the REx will run until it reaches 60% then shut off. If you then leave the rest area and drive back down the hill slower, so that it regeneratively charges the car to 65%, Hold SOC will still be at 60%, so dropping below 65% won't kick the REx on. You'd have to turn off Hold SOC and turn it back on to reset it up to a higher number.