I was just saying technically speaking, the definition of Master/Mistress is someone who has learned every aspect and has mastered the trade from the ground up (any trade really).
I technically call myself a Miss, but wouldn't say Mistress because I don't believe I have earned that title, but I do understand your natural tendencies and would never put that down. To each his own in terms of names, I am relatively new to the lifestyle in comparison to some that call themselves Mistress and I feel like in time I will change that, but that's just my personal preference.
You are correct it does depend on what the couple decide, but then again.. that's also choice!!

Which we know is made coherently prior to any agreements!!!