Supplementary chargesheet is filed only when new evidences are brought on record, which was not in possession of the complainant or the prosecution agency (police in cases of 498a).
The scope of it is very limited.
Also, once the CS has been filed in the court, it is near impossible that any alterations in the same. However, don't confuse the filing of the CS with forwarding of the CS to PP for approval.
And remember fear bordering to paranoia is going to be your worst enemy.
Regards,
Shonee Kapoor
www.facebook.com/shoneekapoor
Handphone: +91-8010850498
Email: harassed.by.498a@gmail.com
Yahoogroups: https://groups.yahoo.com/group/sahodar
If you don't fight for what you want, don't cry for what you LOST.