Hello. I'm new to the forum. I have a new LE6920MP on back order. I am going to add Aimpoint optics if and when it ever arrives. The only major difference I see on the Aimpoint web is the battery. However, there is about a $400 difference in price. The battery is a common CR2032 on the Pro and a AA on the CompM4. Am I missing something here? Agreed the CompM4 battery lasts up to 8 years and the Pro last 'only' 3 years. I don't want to pay an additional $400 if that is the only difference.