That is Wells Fargo's own guideline, master conforming & FHA guidelines just call for the home to be taken off the MLS - no time period is required. Lenders put their own time frame requirements. There used to be lenders who'd do refinance with 1 day off the MLS but the shortest period of time I'm aware lenders are doing is 1 month. The 6 month requirement is standard with a lot of lenders though.
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