I think they are !
Few years ago I was rigging a cambered NP on beach at Sotavento. Mast broke as I downhauled it (a NP X9) They brought me another. ( I was hiring kit luckiliy) and it broke again as I applied DH !!! Chose another rig !!!
My longest mast is 490 so weight penalty on 75% isnt too bad. Only use Tush 75% now. (last 5 years) Yet to break one !!