I use Load From A Disk, a similar program.
I've had great luck with it. That's how I came up with loads for both the 338/375 Ruger and my 375 BME wildcat. The velocity predictions were dead on with the 338/375 (within 10fps!) and very close on the 375 BME after making some adjustments to the internal case volumes.
Pretty useful programs and a ton of fun to play around with.
Andrew