Using OR statement in an expression

I have a scenario where I would like to use the 'OR' statement in SSRS expression.

I have the following fields:

GLnumber, ProgramControl, GLAmount & EscrowDepositAndWithdrawal.

What I would like to do is as follow:

If GLnumber is 12200.22162 then I would like to take EscrowDepositAndWithdrawal

OR

If ProgramControl is 'escrow' then I would like to take EscrowDepositAndWithdrawal

OTHERWISE

I would like my expression to take GLAmount

My expression looks something like this:

=IIf(Fields!GLNumber.Value = "12200.221620" OR Fields!ProgramControl.Value = "ESCROW",Fields!EscrowDepositAndWithdrawal.Value,Fields!GLAmount.Value)

It appears only the first IF statement is true.  It does not appear that the OR statement never be true.

I am not sure why the OR statement never satisfied. I know I have a record with ProgramControl = "ESCROW".

Thank you in advance.