When i had to renew my mortgage (Canadian) I was able to change a few things. They'll send you a document 3-6 months or so before it ends. I changed my payment, and that changed my amortization. I ramped up my payments as much as possible with my budget. Usually they'll send a document and you will have choices of the banks current fixed or variable rates. 1yr, 2yr, 5yr etc. You could keep the payments exactly the same or you could adjust to keep the amortization exactly the same despite the new interest rates.
For this new contract i would treat it like it now is a 20 year since at that point you will have paid 5 down already. Otherwise you'd never finish it. Doesn't mean you couldn't go a bit lower or higher on your payments (if buget was too tight initially). I told them i wanted X as a monthly payment (which was within my 15% change allowed) and the amortization was made to fit that.
If interest rate is higher, something will have to change if you want to keep your payment exactly the same, or keep it now to a 20yr mortgage.
If interest rate is lower, your amortization may be shorter than 20, or your payment could be lower
Really when you sign a new contract it can be a blank slate depending on how much freedom your bank allows. Mine allowed quite a few prepayment privileges. Not all do. Use a 20yr predictor with your 185k principle, and shop around. some places will offer really good rates/bonuses if you switch, and also remember, if you do 5 year amortization the penalties to get out early will be nasty. so be fairly certain you're wanting to stay for another 5 years. Otherwise do something like 2 years.
There's a lot better rates than 5.5% This is who i used. They allow 15% prepeayments, 15% payment increases and double payments. Your big banks usually screw you over compared to other places like this or independent companies that mortgage brokers have access to.
http://www.firstnational.ca/Residential/Mortgage-Rates/