NEW YORK (AP) ¿ Standard & Poor's said Tuesday that Comfort Systems USA Inc. will replace Charlotte Russe Holding Inc. in its S&P SmallCap 600 index after the close of trading Sept. 29. Advent CR Holdings is planning to acquire Charlotte Russe in a deal expected to close on or about that date. Houston-based Comfort Systems provides heating, ventilation and air conditioning installation, maintenance, repair and replacement services. It will be added to the S&P SmallCap 600 GICS (Global Industry Classification Standard) Construction & Engineering Sub-Industry index. Its shares slipped 17 cents, or 1.4 percent, to close at $11.63 on Tuesday before the S&P announcement. In after-hours trading, they gained 96 cents, or 8.3 percent, to $12.59. Stocks often rise after they are added to major indexes as they are bought by managers of investment funds that mirror the indexes. Charlotte Russe shares gained a penny to close at $17.47.