Change in contract help

I am talking to a lawyer next week about this, but just wondering if anybody had any insight?

By November I will have worked for my company for 6 months and so will have 6 month of payslips. I’ve worked there since May 23rd and am paid for the hours I work. However, my contract originally stated me as a salaried employee though I was paid hourly.
My contract changed anyway from classed as Salary to Hourly in August. I was working (probably wrongly) under the assumption my wage slips would be counted from my June payslip onwards, but considering my June and July payslips were apparently salary and not hourly (though I was paid for the hours I worked and not a set sum so I think I don’t understand this either), does this mean that I can only really count my payslips from August onwards for 6 months to calculate my gross annual income?

Basically has anybody ever been in a situation in which their contract has changed? I’m now presuming I will have to work with the hourly payslips until January in order to prove my annual gross income over 6 months as June and July won’t be counted? Or are they still able to be counted as it’s variable income over 6 months?

Please provide more detail.

What is your current visa status and what immigration application are you or your dependants planning to make?