Federal law says an employee is able to change their withholding anytime they want - as often as they want. Your employer is only slightly inconvenienced but they can't stop you from doing it.
When I was working fulltime, my hubby and I had a hard time getting our withholding to exactly what we wanted it to be so we both declared 'zero-married' then had a specific dollar amount taken out in addition to the standard withholding. It was just easier that way.
BTW, you can claim as many deductions as you want on your WITHHOLDING. When it comes time to file, you have to be honest about your marriage status and number of dependants.
As far as re-amortizing the mortgage is concerned, I figured if paying off the debt was so important it meant reducing the amount contributed to the 401k, then cash flow would be tight enough to re-amortize the mortgage (I didn't recommend refinancing) and perhaps increasing deductibles. I hate to see people lose out on their 401k investment and the beauty of compounding interest unless it is absolutely necessary.
Miracle cloths - are microfiber cleaning clothes.
Micro Fiber Miracle Cloth I'm sure they are sold in Canada. I like the really thick ones that are sold in home stores. I use those instead of dish towels in the kitchen. However, I also have a supply of cheapo microfiber cleaning clothes that I use for dusting and cleaning which I found in the auto parts department of most large stores like WalMart.