as far as i know, the top 5 in sispec will be selected for OCS
training.
for those in the enhanced batch, crossing over will require you
to serve that extra 2 months more.
which means you serve a total of 2 years instead of 1 year 10
months.
and yes they still do take people straight into OCS after you
finish BMT 
lastly all the best to you 
i really do hope you manage to become a pilot at the end.