I try not to play fast and loose with the rules, but figured a little extrapolation would work. Here's a burn rate chart.

Powder Burn Rates

Now, my modern reloading 2nd edition lists A nitro 100, bullseye, and red dot as suitable for the 38 S&W, giving burn rates of #5, #6, and #10. Titegroup is #12 on the list, so is in fact slower than the 3 other powders mentioned.

I also don't think Titegroup is the "ideal" powder for the 38, only that it will work. I think Unique is my choice for this caliber.