Laser hair removal fits into your natural hair growth cycle. Basically you're hair has three positions, growing, dieing and dormant. The laser requires the hair to be in growth mode to work. This is when the hair follicle is at its most active and can therefore be destroyed. The usual cycle for hairs is about six weeks.
As the laser will only destroy growing hairs, you should not get treatment more frequently as you are only putting yourself through pain for no result. You also risk destroying skin pigmentation. I have had five sessions and have one to go. It has taken nearly 2/3 rds of a year to virtually destroy the hair on my face. You just need to be patient. As with hormones RLT et al, you need to be patient.
Also, it is not grey hair that is generally the problem. Some grey hairs can be treated as they still have pigment. It is the clear hairs that you have to worry about.
I would speak to your technician to see if both electrolysis and LHR can be carried out at the same time.