Using ProScan, you can simply import your 996P2 file if you so desire. That can give you a jump start rather than starting all over.
Your comments that you were not receiving much of anything in your vehicle (on the trunked system), but did after you brought inside might be a sign of a simulcast problem. The very strong signal is another hint.
What might be happening is this: As already discussed, the OKC site is simulcast. Out in your vehicle, you're getting hammered from different directions, and that can overload the scanner to the point you hear nothing (on the OKC trunked system). Simulcast is generally not an issue on conventional channels, so you are hearing those in your vehicle.
But then you brought it inside, and connected it to a dipole just out your 3rd story window, and voila, trunked system reception. As I noted
earlier, and has been documented & discussed ad infinitum here in the forums, simulcast is extremely location dependent. Bringing it inside, then connected to a dipole just out your window, the stricture of your apartment building may be blocking, or at least attenuating, signals from other directions so that the scanner can work. Foil backed insulation in the walls (in a residential house), or aluminum siding on the outside walls, can have that same effect. In exchanging messages with someone in my area (DFW), the member I was talking to found that moving his 436HP a whopping six inches made the difference between working, and not receiving.
When you were "3 miles SW of downtown OKC", you may well have been close enough to one of the individual subsites (the transmit towers in a simulcast site) that it's strong signal was enough to drown out the out of sync signals from other locations. Here's the site map for the OKC Simulcast (from the database):
View attachment 142949
At home in Yukon, outside in your vehicle, you can see a number of sites scattered around in different directions & distances from your location. The dipole outside outside your apartment window, especially if that was in a northwest or southwest direction, may have resulting in blocking enough other sites to only get a good signal from one location. You can see that there are a number of subsites scattered to your east, at slightly different distances & directions.
I don't have the 996P2, but do have it's handheld sibling. It struggles with simulcast. The 436HP & 5336HP are a bit better dealing with simulcast, but the only scanners that can consistently handle it are the SDS series scanners.