Create formula by combining two formulas

[Plrooff]

I have two similar IF formulas which are populating two columns.  They are mutually exclusive.  Both give the results I want.  I want to combine these formulas so the results of the one that is TRUE populates the column.  I can't get this to work.  I think it may only be a case of structuring or punctuation.  I am trying to use the OR function nested in an IF.

My formulas look like this, where Bank, Month, IntroRate, and Prime are defined for use in formulas:

       IF(Bank="DSB",IF(Month<7),IntroRate,Prime)

       IF(Bank="CCB",IF(Month<13),IntroRate,Prime)

Thank you for any suggestions.

[#2]

@Plrooff 

IF(OR(AND(Bank="DSB", Month<7), AND(Bank="CCB", Month<13)), IntroRate, Prime)

[#3]

Hans,
Thank you. I probably didn't make myself clear.
What I am trying to say with the combined formula is:
If Bank is "DSB" and Month is less than 7, OR if Bank is "CCB" and Month is less than 13, I
want IntroRate, otherwise I want Prime.
Thanks for any suggestions.

[#4]

@Plrooff 

Is this better?

IF((Bank="DSB")*(Month<7)+(Bank="CCB")*(Month<13), IntroRate, Prime)