Is something wrong?

So, I have this wonderful starter. It is established and I have made wonderful english muffins with it and it's awesome. I keep it at room temp, and feed it on a 1:1:1 every 12 hours and it usually more then doubles on that, very active, very happy.   I wanted to try BBA's basic sourdough, so I took some of it and fed it on a 1:2:2 as per BBA to make the "barm" for the basic sourdough.  I left it on the counter and when I came home 6 hours later, it had only increased by about 1/4.  There are some bubbles on the surface, but nothing even close to what it usually does by this time.  BBA says to let it ferment for about 6 hours or until bubbly before sticking it in the fridge.  Am I expecting it to do too much?  In doing some research I've read that most peoples starters have doubled in 4 hours with this ratio.  I took it's temp and it was around 69....too cold? I did notice that the heat had been turned down in the house....Is there a better recipe for a beginner to attempt?  I feel like a bad mom that pushed her kid too soon!