weird o2 numbers

[flyin3]

i just installed the SMC alky kit (old style) after i got it installed i set my boost low...it would spike to say 19 then drop to 16....but when i was making a boost run my 02s were like 040 and bouncing around all over the place...i dont have any idea why it was doing this...i made anotehr pass it was at around 830 what would make the 02 numbers change like this? also should i get a good tune with out alky then try the higher boost and alky?