Your pic is showing a pork butt, NOT a shoulder.
The money muscle is the rounded area at the right.
The butt & shoulder are not the same cut.
You should absolutely be probing for tenderness.
That is not a 20# butt.
Pitmaster @ Lockharts BBQ
I cook the best brisket north of Dallas. Get over it.
Northern midwest director for OBR
BBQ Person of the Year 2013