NEW YORK — Halloween weekend proved more trick than treat for Broadway, with the majority of shows dipping at the B.O. in Week 22 (Oct. 22-28).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. 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 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 Barrino. Bucking the trend on the street, some of the fall’s plays gained momentum, with Aaron Sorkin’s latest, “The Farnsworth Invention” ($250,009), jumping by about $60,000, and the Roundabout’s “Pygmalion” ($282,800) climbing by roughly $55,000. Among tuners, “Hairspray” ($757,610) stood out as the only musical to rise last week, even if it was only by $2,800. The 22 musicals grossed $14,648,017 ($18,419,413 estimated) for 86.1% of the Broadway total, with an attendance of 185,472 at 83.9% capacity and average paid admission of $80.98. The seven plays grossed $2,371,396 for 13.9% of the Broadway total, with an attendance of 40,433 at 79.1% capacity and average paid admission of $58.65. Average paid admission was $76.90 for all shows.