A gradient produces the tidal forcing
A whole-body gravitational acceleration mainly moves Earth together. The tidal term comes from its spatial variation. For a distant mass M at distance d, the leading gradient scales as GM/d³, explaining why comparing mass alone is insufficient.
The real ocean does not follow a static pair of humps
Coastlines, water depth, rotation and resonance change the water’s response. High tide need not occur when the Moon is overhead. Compare observations with predictions for the same station and datum, rather than applying one generic tide time everywhere.
Spring and neap cycles
Around new and full Moon, solar and lunar tidal forcing reinforce more strongly; around quarter phases their alignment produces smaller ranges in the simple description. Weather adds surge and pressure effects. A useful local forecast combines astronomical constituents with the actual basin’s response.