Hello.

You can give improvements in the same year itself that is when gov. Conduct you have to write them though it may be before or after CET Most probably improvements will be conducted before CET. And it doest man taking a drop actually , if you are willing to study for competitive exams then improvements is a time wasting thing. So people often say like that but never mind if you are good at things nothing goes wrong.

Hope this is helpful.

Goodluck.