Obviosuly I dont know your circumstances Bombdr, but if you getting your pesnion immediatly, I would hazzard a guess that its medical related, so the bonus there is a) its Non taxable and b) you carry on getting it forever, so it shouldnt be to long before it overtakes the grant hopefully
If your discharge is for medical reasons, bad luck.
Your pension will reflect your length of service, your rank and the severity of your disability and whether it was caused by your service. The rules changed a while ago, and I will try to remember to check in the morning once I am back on the faster system.
Have you tried the Veteran Agency site or spoken to your RAO?