There's a dispute between tanaim as to when the bikurim were waved (t'nufa): Rabi Eliezer ben Yaakov says they were were waved during viduy, while Rabi Y'huda says they were waved after viduy. (According to Tosafos, Suka 47:2, Rabi Y'huda may agree they were waved during viduy also, and the Sifre says they were waved both during and after viduy, but, anyway, Rabi Eliezer ben Yaakov holds they were waved only during viduy.)
Rambam rules in his Mishne Tora like Rabi Eliezer ben Yaahov.
Now, in M'nachos 61:1, the mishna says "אלו טעונות תנופה ואין טעונות הגשה לוג שמן של מצורע ואשמו והבכורים כדברי רבי אליעזר בן יעקב", that bikurim require waving "as Rabi Eliezer ben Yaakov says". The g'mara asks why it says "as Rabi Eliezer ben Yaakov says" if Rabi Y'huda also holds bikurim are waved, and offers two answers.
Why doesn't it answer "because it means bikurim are waved during viduy only"?