Does an updated return cost more tax than filing on time?
Yes, by design. The updated return is a paid amnesty rather than a free correction: additional tax applies on top of the tax that would have been payable and the interest on it. That is the trade for being allowed to put a missed or incomplete year right after the original and revised deadlines have gone. So the comparison worth making is not against a timely return, which is no longer on the table, but against leaving the year unreported, where the exposure is charged by reference to the return and the delay rather than to the tax, and can outlast the window in which anything can be done voluntarily.
What if the window for an updated return has already closed?
Then the instrument is gone for that year, and no willingness to pay reopens it. This is the part people underestimate, because the route feels like a permanent safety net and it is not. What remains is a year that is unreported, with the exposure that goes with it, and a decision about how to handle it if it is ever raised. We still document it: what the income was, what the position would have been, and why the year could not be filed. A year you can explain from your own file is in better shape than one you have to reconstruct under questioning.
Is there a separate penalty for filing the updated return itself?
It helps to separate the two things. The additional tax is the price of the route. It comes with the updated return and is not a charge for using it. Exposure for the original default is a different matter, and the updated return does not erase it: it is a way to get the income and your own account of it onto the record, not an eraser. Anyone describing the filing as closing the year completely is describing something the instrument does not do. What the filing does reliably is remove the fact of non-reporting, which is the part that grows worst with time.
Should I file an updated return now or wait and see?
Waiting has one certain effect: the window on the earliest year keeps shrinking, and when it closes that year is shut to this route for good. Everything else about waiting is speculation. There is also a practical argument for acting while the papers are still to hand, including bank statements, contract notes and the reason a payment was made, because the computation is built from those and reconstructing them two years later is slower and less convincing. We generally settle the whole run of years first, then file in order, so nothing has to be revisited.
Can an updated return fix a year where I overpaid?
Not in that direction. Reducing a liability you have already declared, or producing a refund, sits outside what an updated return may do, so a correction whose whole point is to get money back will not work through this route however late or early it is filed. It matters on the timing question because people hold off filing a genuine omission while they try to combine it with a recovery in the same year. Those are two different problems. Deal with the omission inside its window, and look at the recovery separately.
Do I file an updated return if no tax is owing?
Sometimes, and the reason is the record rather than the money. The obligation to report a year is decided by the facts rather than by the tax that turns out to be payable, and an unreported year carries exposure keyed to the return and the delay, which is why a nil year can still be expensive to leave open. Set against that, the updated return cannot give you a refund, so there is no upside beyond the record itself. Where a filed history is going to be needed, for a visa, a lender or a sale, the record alone is usually reason enough.
What are Forms 15CA and 15CB for?
They clear a payment out of India. Form 15CA is the remitter's declaration of the payment and the tax withheld on it; Form 15CB is an accountant's certificate on the taxability of the amount, the treaty article relied on and the correct withholding rate. The bank generally will not execute the transfer without them, in the categories where they are required. The work is deciding the rate correctly, because the certificate is the record of that decision. See 15CA and 15CB certification.
Do NRIs pay tax on money sent to India?
Sending your own funds to India is a transfer of capital, not income, so the remittance itself is not taxed. What is taxable is income the money then earns in India — interest, rent, capital gains — under the rules for the account type it sits in. Sending money out of India is the direction that needs certification before the bank will act. See NRE, NRO and FCNR accounts.