Skewing the Figures in our MLS

There is a practice in our Association that has our MLS Committee and Chairperson really concerned. Some agents are taking a property off the market and re-listing at a lower price before accepting a contract at the lower price, thus improving their list to sale price ratio. This also improves their days on market data. For example, a home has been on the market for 120 days at $200,000. The listing agent has a buyer who has offered $180,000, 10% lower than the list price, and the seller has agreed to this offer. The listing agent takes the home off the market and re-list it at $180,000. The list to sale price ratio is now 100% versus 90% and the days on market for that listing is now 1 day instead of 121 days. Is this a common practice in other MLS's? Doesn't this skew the figures and not give a true picture of the market? We are looking for ways to have our MLS track the original sales price and DOM by address until sold.