There is no clear-cut answer on when one will be promoted. Focus on doing your job well and when it comes, it comes. If it doesn't come, don't be overly upset. I am sure that if you will reap the fruit of labour, be it through PB or other forms of recognition. Just keep in mind how you ended up with a C- when you were a BT and not to repeat the mistakes. Btw, it is not about the number of projects that you do. Think about how you have value-add to the organisation. At your grade, T&L will be your bread and butter.