I use my own calculator based off the formula 10MYC for an OG of 1.048. From what I have noticed is that Mr Malty is around 8.5MYC for an OG of 1.048 so I would consider it to be slightly underpitched?!?
On how to decrease lag time, I would say pitching the correct number and giving them lots of O2. Some people think that they are pitching the right amount alot depends on how fresh your starter is, I have taken to brewing my starters from slants starting about 7-9 days out and stepping them up slowly and then day of the brew decant and pitch into a warm up starter, I make this very similar to the brew and don't use a stir plate it is just to wake them up a little. My lag time is usually 6-9hrs and my fermentation time Pitch to static SG is less than 72hrs (accept some of the really big stuff). Fermentation time on my last three beers
IIPA WLP001 OG 1.112 FG 1.018 96hrs
Hefe WLP380 OG 1.054 FG 1.012 30hrs
Pumpkin Notty (from a slant) OG 1.064 FG 1.010 65hrs
Note they all spend my longer in the primary than that to let the yeast clean stuff up, I'm just talking about the basic fermentation.
Clem