A new Federal Housing Administration rule may make it more difficult for potential South Florida homebuyers to qualify for a loan, according to some industry experts. Beginning Nov. 1, the new rule will disallow spot approvals, which allowed loan underwriters to approve individual units rather than an entire building. The spot approval process was attractive to buyers because it provided lower interest rates and required lower down payments than conventional bank loans, said Theresa Schmitz, senior underwriter for Amerifirst Financial in Fort Lauderdale. “This new rule poses a potential downward trend in condo values because many people can’t afford to put such a large down payment down on a condo,” Schmitz said, adding that a downward spiral in the condo market will have an adverse affect on the larger real estate market, particularly on single-family homes. “When the condo assessed valuations plummet, our collective tax base will decline. Single-family homeowners will pick up the slack with a hike in the millage rates and property taxes,” Schmitz said.