CBS comedies again claimed the top four spots in the demo rankings Monday , led by No. 1 show ”Two and a Half Men” — but were down a bit week to week, while ABC kicked off the night with an above-average delivery for ”Dancing With the Stars,” which was trimmed to an hour for its performance finale.

According to preliminary national estimates from Nielsen, CBS opened the night a demo winner with ”How I Met Your Mother” (4.3/12 in 18-49, 10.1 million viewers overall) and ”2 Broke Girls” (4.4/11 in 18-49, 11.2 million viewers overall) though both declined some from their hot showings of last week. Also down a bit in demos were ”Two and a Half Men” (5.2/13 in 18-49, 15.7 million viewers overall) and ”Mike and Molly” (4.2/10 in 18-49, 13.1 million viewers overall), though the absence of ”Dancing With the Stars” competition helped them attract more older viewers and thus their largest overall audiences in more than a month.

Ratings for ABC are subject to revision as the preliminary estimates include a preemption for NFL football in Boston, but ”Dancing With the Stars” averaged a 3.6 rating/9 share in adults 18-49 and 20 million viewers overall in the 8 o’clock hour , up vs. recent weeks but again well behind last year’s performance on the comparable night. It was followed by the debut of alternative series ”You Deserve It” (2.1/5 in 18-49, 10.0 million viewers overall), which performed modestly and retained about the same percentage of its lead-in audience as last year’s ”Skating With the Stars,” which similarly bowed following the performance finale of ”Dancing.” And closing out the night, ”Castle” averaged a 2.7/7 in 18-49 and 11.9 million viewers overall, though these numbers should come down in the nationals.

Fox’s dramas continue to perform sluggishly, with ”Terra Nova” (2.1/6 in 18-49, 6.5 million viewers overall) down a couple of ticks week to week and remaining a distant third among the Big Four in the 8 o’clock hour. And at 9, ”House” (2.5/6 in 18-49, 7.3 million viewers overall) held steady week to week in demos while picking up some older viewers to boost its overall audience.

At NBC, ”The Sing Off” (1.4/3 in 18-49, 4.3 million viewers overall) was up a tick, and 10 p.m. newsmag was down a bit (0.9/2 in 18-49, 3.6 million viewers overall).

CW appeared to be on a slight uptick with its drama combo of ”Gossip Girl” (0.7/2 in 18-49, 1.5 million viewers overall) and ”Hart of Dixie” (0.7/2 in 18-49, 1.8 million viewers overall), with ”Gossip” hitting a season high in total viewers. The net aired the football game in Kansas City, so these preliminary, affiliate-based ratings could be adjusted in the nationals.

Preliminary 18-49 averages for the night: CBS, 4.0/10; ABC, 2.8/7; Fox, 2.3/6; Univision, 1.5/4; NBC, 1.2/3; CW, 0.7/2.

In total viewers: ABC, 14.0 million; CBS, 11.8 million; Fox, 6.9 million; NBC, 4.0 million; Univision, 3.5 million; CW, 1.6 million.