BLDC Motor And FOC Works??

Greetings ..Long time ago I worked on a motor control project. Used a 2kW bldc motor and tried to implement FOC (Field oriented Control)using Hall feedback.Also had interpolated the hall angle to fill in the hall-values between 60 degree intervals. This was a complete failure. the motor was never able to control above 1500rpm . Speed control was good with proper response time. Also the motor made a lot of noise after 1500rpm. The inner current loop was a disaster. While FOC on this BLDC motor was a failure, the six step commutation worked really fine. With this algorithm, the motor ran well upto 3000 rpm smoothly without making any noise when its was rated speed was 2600rpm.

I need to know , the control algorithm FOC on BLDC motor works ? if so, what are the reasons why this approach failed. what could I have possibly done wrong?
Anticipating your kind inputs.