It's simple, and Engine Analyzer Pro is very smart and accurate.
IF you model a camshaft lobe profile that is basically the same between a roller and a solid flat camshaft of course the numbers will basically be the same. All it's looking at is the lobe profile that you asked it to model. There will be some allowance for friction reduction which might be accounting for some HP gain and that can be verified via the analysis data.
The benefit to the roller profile is to get the valve lifting faster, as well as in most cases higher, in a shorter amount of time. In other words the amount of degrees of camshaft rotation to get to .100, .200 and so forth is less with a properly designed roller profile. That is the advantage to using a roller.
As you can see, and Engine Analyzer confirmed this, if there is very little or no difference in lobe profile there will be very little or no difference in power.
As for loosing a lifter. If you ever loose a roller it's a mess as well. Granted, there is no break in on a rolller but when they go, the spew debris as bad as a solid, if not worse. That's not something with a hyd though I'd be concerned about.
Follow the links to the Demo. This is a great program and we use it all the time. We have EA software that links between the flowbench data, cam doctor and then into the Engine Analyzer Pro. Without exception every race motor is designed this way and most of the high performance street stuff. As long as all the data is accurate the end result numbers come out very close to our actual dyno verification. If they don't, we know something is amiss. All of the Performance Trends software is excellent. The guys that work their are all brainiacs when it comes to this stuff, very hard core.