A column I wrote last month on the upcoming 10 percent withholding of income tax on interest and dividend payments brought in several letters on the subject.

Here is sample opinion from a reader who holds a different opinion.

"Your article in The Washington Post on 21 March left me cold! You seem to think that the banks are the only ones that are disturbed about the 10 percent withholding.

"You are misinformed! You are misinformed! You may not realize it--but it's the public who is going to pay and suffer. I'm not worried about the little bit of money that I'll lose because of interest compounding loss (that's all that you and other writers think is involved).

"The real cost (and extra complications on my part) will be the record keeping, paperwork, filing, mailing, etc. (including new computer programs) that the banks will just charge on to their customers ('the public').

"So why don't you stop disseminating that **** that The Post is printing for you--Dole and Reagan will lose more votes because of this issue than they will because of the economy! You don't know what you're talking about.

"P.S. And I'm not connected with--nor do I have any interest in any bank."

No good purpose would be served by arguing the pros and cons of interest and dividend withholding--and the Congress may make the whole discussion academic anyway.

But I should point out that the "extra complications" on the taxpayer's part are expected to involve nothing more onerous than entering the total amount withheld by all payers on a single line on Form 1040, much as one now enters tax withheld on wages or salary.

For the bank or other payer, most--practically all--financial institutions now have computers. What we're talking about is the addition of a single field, or item, to each record, or payee. There will be no extra mailing cost because the total tax withheld will simply appear as another entry on the same 1099 now mailed to each depositor or shareholder.

Not all the mail was contrary. Let me close the discussion by quoting a letter from another reader:

"I want to thank you for your piece of this date. I've been trying my darndest to convince my friends that the 10 percent withholding on dividends and interest law is one good thing Ronald Reagan is supporting.

"I'm tired of some people conveniently 'forgetting' to report this or that dividend--and even bragging about having done so.

"Your column sounded very convincing to me--but then I didn't need convincing. I wish somehow you could make it required reading."

Question: I've just filed an income tax return for my dependent son because in 1982 he had unearned income greater than $1,000. I was surprised to find that the tax computation formula eliminated the zero bracket amount since I had to add $2,300 to his income, thus making all the income above the $1,000 personal exemption taxable. What is the logic behind this?

Answer: The zero-bracket amount (ZBA) is eliminated on the individual return of a child because one ZBA is already allowed on the parent's return, on which the child is claimed as a dependent. It is unlikely that a dependent child would duplicate the same kind of Schedule A-type deductions (like mortgage interest and medical expense) as the parents. The ZBA is a minimum allowance for those kinds of expenses when the taxpayer doesn't have enough to make itemizing pay off.

If the child does in fact have some of those expenses, remember that you may attach a Schedule A to his return on which you claim all valid deductions attributable to his income.

Tax Tip: The IRS reports that a surprisingly large number of taxpayers appear to be overlooking the new-for-1982 deduction for two-earner married couples.

If you filed a joint return and both husband and wife had earned income, you were eligible for a substantial tax saving.

If you missed it, you can still file Schedule A with an amended return on Form 1040X to claim the deduction and a refund.