MP2759 and Schottky diode

Hi,
can you explain what is needed the schottky diode across IN and PMID pins? Datasheet states for 40V/2A rating but in EVB there’s a B140 - 40V/1A, so is it sufficient 1A?
Also, the difference between MP2759 and MP2759A is only Jeita charging profile?

Thank you

Edoardo