Rebar Specifications

Quick Question: I have a large project in SoCal that includes the following rebar spec language:

“Average recycled steel content such that the post-consumer recycled content plus one-half of the pre-consumer recycled content is not less than 95%. The intent is that 85% of tonnage meets this requirement.”

Is it reasonable to ask for a still higher % of tonnage meet this requirement without attracting cost of is this typical and basically best practice?

Thanks!