My interest field doesnt show either. but i am able to solve my problem. If you have online banking integrated into your QBO, go to the banking page. If you earned interest in savings, you will have a deposit from the bank that you can accept as interest earned. It will then be there in the list of deposits when you reconcile. If they charge you interest, accept it from the banking as interest expense. It will again show with the expenses and you can then include it so that you get a balanced reconcilliation.

So to summarize, make sure you have an entry for either an interest earned or interest expense. It will then show in your reconcilliation on the second page in amongst the other amounts.