Americans apparently found it easier to fill out their remodeled 1977 income tax returns, making fewer serious errors than in the past, the Internal Revenue Service said yesterday.

IRS statistics compiled from the 84.6 million returns processed also showed the average refund this year hit a record high of $476.85, surpassing last year's $446.50.

The statistics showed that the error rate on the short form was 4.9 percent this year compared with 11.8 percent last year - a 58 percent reduction.

For the long form, the error rate was 5.7 percent this year, one third below the previous year's 8.5 percent.

The IRS introduced the revamped forms this year with much fanfare and claims that almost 70 million hours of paperwork would be saved.

Federal tax collectors also hoped to see a substantial reduction in mistakes because the 1040A "short form" required no multiplication and the number of lines to be filled out were reduced from 25 to 15.

The 1040 "long form" also was reconstructed. In the past, taxpayers had to flip the form back and forth to complete it properly. The new form allowed taxpayers to progress straight down the front page, turn it over to the back, and complete their calculations.