I don't use NSI gel but you may need to change a couple of application techniques to cut down on heat spikes...make sure gel is not applied too thick and if a client has a damaged nail plate they will more than likely feel a heat reaction so when the hand goes in the lamp ask them to take it out after 5-10 seconds, put back in the lamp and repeat the in-out 3 times which will reduce the exo-thermic reaction.
Hope that helps a bit, good luck xx