you are changing that 3.73 number to 3.65 right?
I believe thats the firmware your going to not the one your on currently.
Also have you tried it with and without the memory card. You may have lost whats on that memory card because it will also tell you its wrong IF YOU DO NOT format the memory card as it stores info on current firmware used.
it may be that you haven't actually downgraded so your vita is still on a higher firmware but wont let you boot as it corrupt. so its possible if your trying 3.65 firmware you need to go back to 3.73 and use moduru again.
it too me about 2 or three trys and i thought i was done for but i just re did the steps and got there in the end
my advice from here would be remove the memory card and try and as long as QCMA Says 3.65 you should be fine. although this point i think also try going back to 3.73 and re downgrade firmware*remember to change QCMA(. Maybe someone else with more knowledge on the subject will chime in as this seems strange to me as ive seen a few softbricks now but there always seems a way around.
EDIT PS
Dont give up you will get there im sure. it sure is frustrating and that why i keep an eye here for new users who possibly are less confident or less sure of what to do
after it happened to me i was ready to give up but with enough triyng i got there and so will you
and trust me ive seen worse situations lol