Farmers have been warned to check the scale of fallbacks before they sell their milling wheat.
Growers need to calculate the likely price of their crop once it has been sampled rather than looking at the headline price bid, grain merchant Glencore Grain said.
Higher screenings and low bushel weights in some varieties, notably Malacca, means the level of claims made this season is likely to be higher than usual.
The higher claims and differences in fallbacks across mills means some farmers may be better off selling their crops for less rather than risking their wheat being rejected.
“We have seen differences between fallbacks for the last couple of seasons, but it seems to be really noticeable this year,” Glencore grain trader Angela Gibson said.
“It’s sometimes better to go locally for £85/t rather than selling at £90/t and risk a big claim or rejection.
Farmers need to be aware of fallbacks and match the right home for their wheat,” she said.
Ms Gibson said premiums for milling wheat were the highest they had been for some time, at £10/t over feed.
However, there was uncertainty about crops yet to be cut.
“There could be more of a quality problem in the north as harvesting progresses, so we could see some deterioration in Hagbergs,” she said.
“We have seen some low-quality crops this season.
I would be surprised if many farmers put Malacca back into the ground because of low weights.”