Lee, I can only go by what you say.

If all you did was take off the sprocket, flip the washer, then reinstall the sprocket and TDC on the crank matches up With TDC on the cam - then your timing is exactly 180* degrees out.

You must do whatever you feel most comfortable doing to turn the cam 180* without turning the crank and the IP timing gear.

you have two (reasonable) options: leave the rockers in, set lobes up, take out sprocket, turn crank 360* (not my favorite)

The other option:
remove the rockers,
set lobes down and crank to TDC,
remove sprocket,
turn cam to line up the mark with the washer notch,
put on sprocket and chain after arranging the sprocket so that its keyhole matches up with the key on the cam while the marks stay aligned.

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