Even the most arcane issues in tax revision strike directly at the bottom line.

Take an obscure real estate tax advantage that came up for discussion in the Senate Finance Committee yesterday. According to figures released by Sen. George Mitchell (D-Maine), it enabled three large publicly held homebuilding firms to receive tax refunds totaling $29.4 million. Without it, their tax bills together would have been $13.1 million.

The tax-revision bill approved by the House last year would limit that tax advantage, but the measure proposed by Finance Committee Chairman Bob Packwood (R-Ore.) would leave it intact.

The tax break, called "builder bonds" for the debt issues they permit, is just one of the complex and high-stakes accounting issues discussed -- but not decided -- by the committee yesterday. Like the others, it pits one industry against another, pits consumption against saving, is heavily lobbied and affects a wide range of companies.

All the accounting proposals concern basic tax rules by which companies decide when income should be recognized as taxable and how deductions should be related to income. The House bill would raise $57.5 billion in revenue over five years by redefining those distinctions; the Packwood plan would raise $53.5 billion through a somewhat different set of alterations.

"I appreciate that this accounting section is arcane and causes most of our eyes to glaze. But it's big money," said Sen. John H. Chafee (R-R.I.).

The builder bonds work this way: A developer builds a subdivision and lends the money for the mortgages to the buyers himself, through a financial subsidiary. He then uses those mortgages as collateral to borrow money or to issue bonds in order to build another subdivision.

When he gets the loan, his financial position is similar to what it would be if all the mortgages were paid off, giving him income. But he does not have to declare that money as income for tax purposes until the mortgages actually are repaid some years later. Meanwhile, the developer can deduct all his costs currently. The result, the Treasury Department, most House tax writers and a few senators contend, is questionable tax policy.

"If you want to assert a principle, you have to get rid of builder bonds," said Sen. Bill Bradley (D-N.J.).

The homebuilding industry, which increasingly uses the technique, is lobbying for builder bonds, and a cooperative of 90 builders, called American Southwest, has hired the Washington firm of Bracy, Williams & Co.

They are making their case on the grounds that the tax break helps lower-income Americans buy homes. But almost by accident, they have found themselves pitted against another industry group: retailers and wholesalers.

The confluence has occurred because retailers also sell their products on credit, and, in the case of long-term sales, can borrow against money owed them. The House legislation included exemptions for installment sales of less than nine months, which would exclude all but big-ticket sales; the Senate has no such exclusion. Packwood was blunt yesterday in explaining why.

"This was deliberately designed to help homebuilders," said Packwood, who has made no secret of his desire to boost his home-state industry of timber. " . . . I'm trying to do everything I can to limit consumption and consumption financing."

But Packwood also was outspoken about another agenda: The administration tax proposal and the House bill, he said, were kind to retailers because that industry was one of those supporting the tax-overhaul effort.

Retailers "were left out of the House bill for political reasons," Packwood said. "I put them back in as a matter of equity."

The debate was similarly intricate for a host of other accounting issues discussed yesterday, affecting companies from tiny shoe stores to giant defense contractors. None will be decided until the committee takes up the plan again, beginning on April 18.