How much per month do you spend on the card on average? If it's not a significant amount of your $11k limit, they may feel your CL is sufficient for your spending.
If they raise your CL they have to allocate cash reserves equal to a percentage of that new limit to a reserve per the lending laws, and that's money they can't extend to other customers who may be spending far more and therefore have a greater need for higher limits.
if you're running $8-9k through the card each month, then your odds of an increase would probably be really good. If you only use a small portion, then raising it isn't really necessary as you aren't even approaching the limit you already have.
