Anyone ever cut one of these back. Did it  spread new tops or just grow one new top from a shoot at the cut line.

From the photo, the tree appears to be a 'cook pine' Araucaria columnaris. 

 

The short answer is don't top it unless you have to. You will radically alter its natural tapered form and beauty. There are some big disadvantages aesthetic and structural for doing this.  And its probably unnecessary, the trunks and leaders are strong and supple and don't fracture or uproot easily in my experience. Exceptions due to structural defects, site conditons and extreme weather are always a possibility. 

 

The longer answer is yes, I have worked with many cook pines (and relatives in the genus, Norfolk Island pine, Bunya pine, monkey puzzle) that have been topped.

With a minimal crown reduction cut near the top (like one meter max on your pictured tree) to suppress apical dominance and vertical shoot growth,  and If they have adequate water and fertility, they usually do re-sprout within a month or two, with multiple new shoots in the area of the topping cut.  That results in a stubby, dense, bushy top which is kind of ugly. Without professional selective thinning and re-structuring in a year or two, the bushy growth will increase in volume and create more wind resistance and weight at the top in the long term, two to five years and more.  The new shoots have only superficial attachments on the outside growing layer at the topping cut and as they grow up, are prone to breaking off during a wind event, more so than the original undisturbed tapered top. 

 

TreesAreGood Consumer Brochur Why Topping Hurts Trees