Seat attachment on floor boards or murphy's law

As i was getting the second floor board ready i had one of these feelings where maybe i should check that these bolts welded on align with the seat base. They don't !!!!

So i drilled new holes, removed muts from the old floor (seemed stronger) and started to spot weld in place, only to realize that these nuts have had it !

So i wasted my time and now i have to remove them again ! Argh only good thing is that i get to confirm how strong these spot welds really are... (Look strong sigh)