If 'true(1)', attribute values in this DsL2Access element will take precedence over values in other entries when multiple elements are members of the same block and a single value must be chosen to represent all of the block members. For example, a metered policy with a block of filters requires a single in-profile-action be specified. This attribute is used to identify the master block member from the block member list from which the in-profile-action will be derived. A value of 'false(2)' indicates that, if this element is the member of a block, attribute values in this element will not explicitly take precedence over values in other block member elements. Multiple block members may have the value of this attribute set to 'true(1)'. If multiple block member masters are defined or if all block members have the value of this attribute set to 'false(2)', value precedence is determined using element evaluation precedence (i.e., the block member with the lowest evaluation precedence acts as the master when necessary). Version 1/2 attribute.