2000 Jeep Cherokee Oil capacity

Hello,
Start with the fact that I feel like an idiot here. Have 2000 Cherokee with 4.0L six cylinder. According to the manual this motor has an oil capacity of 6 qts.

Just changed the oil for the first time (recently purchase this vehicle), drained old oil (completely), changed out old filter and added 6 quarts of oil. Restarted the engine (all good, no funny noises), let it come up to operating temp and then checked the level.

Here's the rub - the dipstick now indicates that there is too much oil in the crankcase.

Additional data - I added one gallon of Penzoil, plus an additional qt - last time I checked that is six qts (per the manual).

What'd I miss? And do I have to drain some oil out.

Thanks in advance.
Don