“So it seems I can make a berachah,” said Mr. Braun hopefully.
“In practice no, since some limit this position to a salaried worker who is paid by the hour or the day [po’el],” said Rabbi Dayan. “In the common case that the worker is paid a flat fee for the job [kablan], the employer would not make the berachah, even if it’s a Jewish worker.” (See Pischei Teshuvah C.M. 427: 1; Aruch Hashulchan C.M. 427:3)
“Moreover, other authorities disagree completely with the Machaneh Ephraim,” concluded Rabbi Dayan. “They maintain that only regarding acquisition is the employee’s hand like the employer’s, but not regarding the fulfillment of a mitzvah. Therefore, on account of safek berachos l’hakel, you should not make a berachah. Only if you complete the mitzvah and attach the final piece of the ma’akeh can you make the berachah.” (See Nesivos 188:1; Minchas Chinuch 216:6, 546:3, Sedei Chemed, Asifas Dinim, Maareches Berachos #16.)