I say, with the tide going out (in) and the wind going sideways (left ways,
no,
right ways), lots of times the boat can get a fair amount of way on while you
try and sort it out.

If there is substantial wind and/or current you wil be using the throttles as
well as the gears. 10th of a second? Long before you push the throttle as far
as it would take to make a gear change, you will indeed notice a pronounced
change in RPM. The error will be immediately apparent. There shouldn't be any
"trying to sort out" involved. If you screw up in the middle of a landing, you
have to know how what you did affected things and have a plan to counter or
recover. It's way too late to sort anything out. You either have a workable
program to recover or you abort and start over.

Situational awareness. Don't leave home without it.