Should I Try to Renegotiate my Mortgage?

We are planning to refinance our mortgage by the end of May this coming year in order to roll in some debt related to adding central air to the house. When we bought the house last June, we financed with an 80/20 loan program and paid just a small amount down along with all closing costs.

The first mortgage is with CitiMortgage (C) and our second is with Countrywide (CFC). The original purchase price was 183,000 and we have done substantial work to the house, including slate roof repairs, electrical service upgrades and the central air install. The central air was a high efficiency Unico System because of the need to preserve our old home. The cost for the system was just over 16,000. It is currently financed with CitiFinancial (C) with a 1 year no interest plan (we had planned from the start to refi and roll this balance in).

By the time we refinance, we will have less that 180k left to pay on the two mortgages plus the 16k from the central air. That means we will be needing to finance 196k or so. Back in the day, that wouldn't have been a problem. Now, it's much harder to find a "cash out" refinance for anything more than 90% of the appraised value. We won't have any problem getting an appraisal to come in at 210k or so, but with 90% that would mean we would need an appraisal of nearly 218k. That might be a stretch.

Then, a thought came to me. Since both the first and the central air on with divisions of Citigroup, do you think I would have a shot just getting them to roll that other balance into our current mortgage? I mean, they would still have less than 80% of a newly appraised value and we are very good customers with great credit. It would allow them to keep some good money rather than losing it if we refi and go elsewhere.