I have a somewhat different (multi-part) question on the same topic:
IF you have double-cousin relationships in a family tree, and since this theoretically suggests more DNA locus matches than for a single cousin relationship, will AncestryDNA estimate the double cousin to be closer to me in generations (e.g. a "3rd or 4th cousin") rather than a proper placement in a more distant generation (e.g. "5th or 6th cousin")? That is, does the double-cousin linkage "fool" or confound the generational placement estimated by AncestryDNA?
In addition, does double-cousin linkage artificially increase the confidence level (e.g. "95%") of AncestryDNAs for a suggested match?