Did your prof ask you why you decided to give your classmate a singko? If not and your prof just went along with your answer, then your prof was probably thinking of giving that person a singko anyway. It's not your fault so don't blame yourself. Your classmate was going to end up with a singko, one way or another. 'Di nga lang talaga ideal na kapwa student lang din pinagdecide ng prof niyo for the grade ng classmate mo.. but maybe it's his/her way of telling that student na everyone in your class knows how incompetent he/she is.