If your load shoots great, why change it? What you will find as you increase the powder charge in a load is that the groups start out as not so great, then they get better and maybe excellent and then, as the charge is increased they start to widen again. Go ahead and increase your powder charges in 0.5 to 1 grain increments (depending on how close you are to a maximum published powder charge). If the group sizes with charges are bigger than what you are getting now then there is no good reason to use bigger powder charges.