i'm also calculate to 25~30 rubbers
Yeah, it may be that, and it depends.
What I a stated /36-42/ is for a strong and thin glue like Xiom iBond, applied with one layer on the blade and one layer on rubbers with up to middle pore size.
If you use Tibhar Clue, which is thicker, or Falco, which is thin, but weaker, or the rubbers are with greater pores, and/or your layers are generally thicker, and/or you like to apply 2 or more layers on the rubber, than you'll need more glue for a rubber.
Anyway a bottle of 90 ml in the OP case is a bit /or much/ more than he needs. There is a risk to end with at least a half of that useless because of different reasons. Of coarse there is a chance to use it happilly for some 4 years.
Edit: I forgot to mension that it depends /and it really may dpend a lot/ on the blade outer ply kind and surface smoothness