I do not know why the distribution of your mortgage payments to principal and interest change from month to month. On a fixed-rate loan, the amount applied to principal generally increases slightly with each month. However, the application of payments on home equity lines can be somewhat more unpredictable, especially in case you are still making charges on the equity line, thus increasing the balance.
If you think your payments are not being applied to your accounts properly, contact your lenders to discuss the problem and learn how your payments are being credited. If after speaking with your lenders, you still believe your payments are not being credited accurately, you may wish to contact an attorney to discuss what recourse you have against your lender. However, I expect that once you speak with your lender, you will find your payments are being properly applied, as it is unlikely your lenders purposefully misappropriate your funds.
Based on the information you provided, I cannot tell you whether a refinance loan will save money over your current loans, though I certainly encourage you to consult with various refinance lenders to discuss the options available and the costs and benefits of refinancing your home. The 4.75% interest rate you are paying on your current primary mortgage is certainly a good interest rate, especially considering that the average rate on a 15-year fixed rate loan is 5.54% (as I write these words in 2007). Given this fact, I doubt a refinance lender will offer you a better interest rate. However, it certainly will not cause any harm to discuss your situation with lenders to find out if combining the two loans at a slightly higher rate will save you money over your current loans. Visit the refinance page to read more about refinance loans.
I wish you the best of luck in your search for a refinance loan that fits your needs. I hope this information helps you Find. Learn & Save.