Spouse Visa Variable Income @ 19,800 Annual.

Hello guys! Nice to meet you.

I'm new to this board, this is actually my first post but I plan to use this a lot in the future.
I have a question regarding the income requirement of 18,600 per year, I have just gotten off the phone with a Visa advisor and they seemed to have helped me with their professional advice however some others opinions or experiences would be very valuable to me.

Basically, I work a continental shift pattern, so 4 x 12 hours and then 4 days off, maybe once or twice(very very rare) a year I get a month that pays 1410 GBP as its a short month and I only get 13 days of work, however most months I get 1735, with some 1627 months also, my annual earnings is 19,800 when I took the next 6 months from the calendar all calculated, I divided them by 6 and multiplied by 12 which gave me 19,800. Even the average, so my 9.04 wage, x 42(average hours p/week) x 52(weeks worked p/year) = 19,743.

Does this cause any implications, I know there is a category which is not salary based and accounts for variable income, therefore that's where my application goes, I think.

Your opinions would be greatly appreciated! My life depends on it, lol.
Thank you Guys!!!!