Few questions on Appendix 2 Financial requirements

[qip]

3.20 What was your sponsor’s total income (before tax) from salaried employment in the 12
months prior to the application?

Is it meant in the last tax year or basically since the day I would submit a visa and I cant use numbers from p60.?!

3.21 Does your sponsor’s annual income (before tax) from their current salaried employment
meet or exceed the financial requirement you must meet?

I ticked Yes

3.22 If your sponsor has not been employed by the same employer for 6 months prior to the
application does their total income (before tax) from salaried employment received in the
12 months prior to your application meet or exceed the financial requirement you must meet?

I don't get it. I've been with the same company. But my salary increased in the last 4 month, because I started to do night full time instead of overtime.

Previously it was 30 hours contracted and overtime. Do they take an overtime into account? In last 6 month period for two month my salary fluctuating from 270 to 320 for two month,but then,when I've got night contract, I'm getting more. After calculating all my payslip it's work out I've earned more than £9300 in 6 month period (but it include overtime payments).
Question is,is the overtime counts?
What I have to answer in 3.22?