The Taxpayers Bill of Rights II formally known as the IRS Reform and Restructuring Act codified in part as IRC §6330 provides that collection activity stops when the OIC application is filed. When you file the OIC, they will notify you with form 4143 that they received the OIC application. Our interpretation of the law is when they receive the OIC form and acknowledge they receive it, and then they must stay enforced collections. This is explained more on their website:
http://www.irs.gov/irm/part8/ch15s02.html