Halloween weekend proved more trick than treat for Broadway, with the majority of shows dipping at the B.O.

Heck, even estimates for the much-hyped “Young Frankenstein” — whose producers have decided not to report weekly sales — fell off by about $100,000 to $1.4 million. (But don’t feel too bad for the new Mel Brooks tuner: That tidy sum is for just seven previews, as was the previous week’s tally.)

Including those unofficial “Frank” estimates, total Rialto cume was down by more than $450,000 for 29 shows on the boards. Some legiters attributed the slippage in part to the run-up to Halloween, increasingly a party-for-adults holiday that distracts from legit offerings.

Among the officially reported numbers, the largest dips of the week were seen by “The Drowsy Chaperone” ($498,972), off about $105,000; “Les Miserables” ($455,038), sliding more than $80,000; and “The Color Purple” ($788,545), sliding by just under $75,000 due to the illness of the show’s star Fantasia. (She’s due back this week — as is Roger Bart, one of the stars of “Young Frankenstein,” skedded to return last night after back problems kept him out of several performances.)

Bucking the trend on the street, some of the fall’s plays gained momentum, with Aaron Sorkin’s latest, “The Farnsworth Invention” ($250,009 for seven previews), jumping by about $60,000, and the Roundabout’s Claire Danes-starrer “Pygmalion” ($282,800) climbing around $55,000. The recently opened “A Bronx Tale” ($257,818) stepped up by $40,000, and the new Rialto outing for Tom Stoppard, “Rock ‘n’ Roll” ($396,619), went up to seven previews from two the prior frame, and had an additional $250,000 to show for it.

Among tuners, “Hairpsray” ($757,610) stood out as the only musical to rise last week, even if it was only by $2800.

Otherwise, B.O. dips ranged in size from the $60,000 seen by “Curtains” ($756,068) to the miniscule $851 drop of “Xanadu” ($280,235).