Married couples would only face a higher charge if the annual assessment remained the same. The assessment can be reduced to accommodate the new system. Saying it would double is totally inaccurate
If based upon per person assessment, such as Sun City West, the assessment is double for a married couple. As I have done some research on other communities offering per person assessments, it is double the amount for a married couple in the same household.
Your original post makes it sound like the property assessment would double. The assessment will have to be higher for two person deed holders to offset the lost revenue from single deed holders.