While the current upfront ad sales market has begun to simmer, a new analysis notes that it may not be as easy as it has been in the past to bring it to a full boil.

Variety’s Brian Steinberg writes that in the annual haggling between Madison Avenue and TV sales executives over the cost of ad inventory, “this year appears more contentious than in the recent past, according to three media buyers and other executives familiar with the tone of these early discussions.”

Steinberg quotes one buying executive saying the talks have become “a little more adversarial than last year.” The exec added that “there is more of a frustration level across the board on the buy side and the client side.”

Meanwhile, some forecasters are expecting a slight uptick in upfront volume this year.

“At issue: The ad  rates the networks are seeking,” Steinberg writes, noting that the two sides are “bickering” over CPMs, with the networks “making the case they deserve CPM hikes that are well in excess of anything they got last year, according to executives.”

We encourage readers to click on the link above to Variety to read Steinberg’s insightful analysis.