job title for perm processing for GC

[hectar]

Hello, I need some clarification in filling for PERM for GC with Job Title.

I have bachelors & masters degree(usa) in mechanical engg and I joined company A after masters, now i have completed 3 yrs with company A, i never worked with any
other company in my life,my title from beginning of my employement has been DBA, now my employer is saying that he cannot file PERM with same title as I do not have
any prior experience, he is suggesting me that he is going to file it as Database analyst which has some similar responsibilities.

Is it true that company A cannot file my PERM with DBA title as I have been working with them with same title for past 3 yrs with no prior experience?

Also,if company A changes my title at PERM and in future if i decide to change employer, will i still have same priority date? or is it going to change
as I am going to change title on PERM back to DBA?

please provide expert advise? Huge Thanks