Please explain Surf Rod Lure Weight

Hi,

I searched and found little information about Lure Weight. For
example, a Lamiglas Ron Arra Surf Pro 10' rod has a lure weight of "3/4
to 2 1/2" and the 11' has lure weight of "1 to 5". What do they mean?
For the 10' rod, if I use cut bait plus a 4 oz sinker and cast hard,
would I break the rod because cut bait weight = 1.5 oz + 4 oz sinker
weight = 5.5 oz total? Or the weight of the sinker is immaterial? I
want to know because I have broken a graphite rod rated at lure weight
= 3oz and I used a 4 oz sinker. Was it a bad rod ($40 Ande graphite
rod) or I exceeded the rating of the rod? If the lure weight is the
total weight during casting the rod can handle, then how is it going to
handle and big fish? I am confused.

Thanks