Since when do we read Shema in Arabic? From the time the poor man entered to eat his pita bread with salt?

Greetings to the rabbi.
 
In Tractate Berakhot, page 2: Rashi writes about the time of the ‘poor man who enters to eat his pita bread with salt’ because the poor man does not have a candle to light it, and therefore he begins and finishes eating early (meaning there is still light). However, at the end of the page the Gemara concludes that the time of the poor man is later than the time when the priests enter to eat their offerings (the coming out of the stars). If this is a late hour when there is no light, then why did Rashi write that this is the time of light?
2. Tosafot ד. ה. אי סלעלק דאתך האין דאלה׃ They ask how it is possible to say that the time the poor person enters to eat is the time for reciting the Shema, since it is forbidden to eat before Aravit, and they give an excuse there that the time for the Qash is the time when the poor person’s meal is prepared. To me, the whole question is strange. It is clear that when the baraita says from the time the poor person enters to eat, it does not refer to a specific second of the day, but to a general approximate time when most of the poor eat. So what exactly is this question of Tos’s, as if the time for eating and the Qash are supposed to be at the same time?
 
Thank you very much.