This appears to be an August deal where you buy a family pass for $55, normally $110 (2ad, 3ch). It is for the garden/gallery experience.
I think you can buy it for a specific date or as a open date pass (i am not sure how long it would be valid for but there was a FAQ which said they would honor passes for 6 months if you needed to change the dates so maybe something like that?).
The Sculptureum is a walk through gardens and galleries just outside Matakana Village. The is a restaurant there but it is additional (they say you can’t bring food in). Recommendation is 2-3hours, wheelchair accessible.
Sorry if this is incorrect somehow - I’ve never posted before!
Is it the attractions family pass that you're referring to OP? (just making sure I've got all the info right).