Question

Hello Rabbi,
 
In tractate Berakhot 2b, Rashi writes regarding the time of “the poor man who goes in to eat his bread with salt” that the poor man has no lamp to give him light, and therefore he begins and finishes eating early (that is, while there is still light). By contrast, at the end of the page the Talmud concludes that the poor man’s time is later than the time when the priests go in to eat their terumah (nightfall). If so, we are talking about a later hour when there is no light, so why did Rashi write that this is still a time of light?
2. Tosafot, s.v. “Ve-i salka da’atakh,” ask how it is possible to say that the time when the poor man goes in to eat is the time for reciting Shema, since it is forbidden to eat before the evening prayer. They answer there that the time for Shema is the time when the poor man’s meal is prepared for him. To me the whole question seems strange, because obviously when the baraita says “from the time the poor man goes in to eat,” it does not mean one precise second in the day, but rather a general approximate time when most poor people eat. So what exactly is Tosafot’s question—as if the time of eating and the time of Shema are supposed to be exactly the same?
 
Thank you very much.