Thanks for your time for reading my post

My query goes like this:
As per the rules, I MUST maintain 2800GBP in my account for 3 months prior to the date of application.
My problem is this that I have 3-4 credit transactions in my account due to which my balance gets below to 2650-2700GBP (approx) than the required 2800GBP (thanks to daily fluctuations in exch. rates

But it stays below the minimum amount for FEW days only.
Now, come to the real point:
Do they consider the statement on monthly basis? That is, they look at the balance of the account at the end of every month of these 3 months?
OR
They look at each transaction being made and if gets below 2800GBP they won't award points for that?
Secondly, what date of currency rate they will consider:
My last transaction of the the claimed period? Or the transaction date of the amount I am claiming for, that is, salary?
Thanks,