the analog one is discontinued at RS, and they blew the last ones out at a great price, and I'd be shocked if you found one (Get it if you do, though it should ring up less than $30). So yes... get the digital one.
I'll bet you're pretty close, though, because that crappy app is at least consistently crappy... so it should be off similarly in all but the sub channel... that'll take a better measuring tool. No tiny 'smartphone' microphone is going to be very accurate at lower, home theater level frequencies.
mods, can we have a 'dislike' button ?