Now, in this day and age, nothing as complicated as a switching power supply, what with all the careful designing and layout needed for loop gain, phase delay, and all that stuff, never gets done right without assistance from qualified experts in this narrow field of endeavor. Particularly, in switching power supply development, until you get all the coefficients set just right, there can be some interesting experiences during bench test. Well, Keith, we think you should adjust this resistor to this value to solve that start up droop problem you described. Well, that was spectacular, you get the halon bottle, I'll go for the hose, you there, call the fire department. You gotta watch stray capacitances, and ground plane impedances can be a real problem, too.
Detailed instructions are available on request.