lying about percentile

why do kids do this? i stopped preparing for jee in august of 11th grade and started preparing apply to the usa because i knew right away i wouldnt be able to do as well in jee as i would in the usa. i got into some unexpected colleges (like uiuc,uw madison etc) but recently jee results came out and every single kid around me got a 99+ percentile.. while i understood some of those results there was this one kid i thought was really dumb.. and he would often degrade me for applying to the usa and pussying out of jee. kids that are secure dont do things like that. this one day i asked him whether an n type semiconductor was negative and he said yes (maybe this is not a very basic question but for 99 percentile??) anyway his result rolled out and his mom called my mom telling her about it. she changed the percentile from 98.4 to 98.8 in that very call. the next day when my mom met the kid (shes an organic chem prof at a university) she asked him his individual percentiles.. he knows that if he lied about chem she would catch him cuz she knows hes weak at chem.. he said 100 for physics 99.2 for maths and 88 for chemistry.. little did he know the math tuition he goes to posted the results of all the kids that got a 99+ for maths.. (his name wasnt on it) i felt so horrible cuz everyone around me was doing so well even without their parents having to spend crores-even though i got into great colleges but now i feel angry so angry. did he think he wouldnt get caught?