Hello aspirant,.

I hope that you are doing absolutely great.

With reference to your above mentioned query, i would like to tell you that there are no criteria that your class 12th percentage will decrease by 5 % if you take a drop for 1 or 2 years. This is just a rumor.

You can take admission in West bengal Engineering Colleges if you clear your WBJEE Examination.

Since you're a WBJEE Aspirant, you can follow teh below mentioned link to know more about the exam :

https://engineering.careers360.com/articles/wbjee

I hope that this will help.