REASONABLE RETAINAGE means an amount, not to exceed 5 percent of available construction proceeds as of the end of the fourth spending period, that is retained for reasonable business purposes relating to the property financed with the proceeds of the issue. For example, a reasonable retainage may include a retention to ensure or promote compliance with a construction contract in circumstances in which the retained amount is not yet payable, or in which the issuer reasonably determines that a dispute exists regarding completion or payment.