Navigating Talent Holdback Requests for Commercial Buyouts

I recently handled a commercial where the agency requested an extended talent holdback for a specific market, which then became a full buyout. This immediately flagged for me that standard union agreements (ACTRA/UDA in Canada, SAG in the US) have very defined limits on holdbacks and buyouts, especially when converting from one to the other. To manage this effectively, I created a detailed spreadsheet mapping out the original shoot dates, the proposed holdback periods by media type (broadcast, digital, OOH), and crucially, the union's maximum duration for each. This allowed us to visually see where the agency's request exceeded union guidelines well in advance of the shoot. What worked was having a clear, documented breakdown to present to both the agency and talent, highlighting the cost implications of exceeding union limits. What didn't work initially was assuming the agency understood these limitations; we had to educate them on the specifics. We ended up negotiating a tiered buyout that respected union rules for the initial term and then had a pre-approved, higher rate for any subsequent renewals beyond that period. Do other department heads find they're increasingly needing to educate agencies or clients on these production-side union specifics, or is it typically handled entirely by PMs/ADs in your experience?