subscription vs services product tracking

Hi SF Community,

We have two different pricing models, a monthly subscription + flat add on fees. When building out a pricebook, I have had trouble creating two separate ways to calclulate them via the pricebook to opportuntiy roll up summary, see my work below:

Contract Term (# of Months) : 12 Months 
Monthly Subscription Cost: $1.00 Monthly (opp product Sales Price)
Total Product Quantity: 1,000   (opp product quantity)
=24,000 Annually (Contract Term * Monthly Subscription * Total Quantity)
However, when trying to add an hourly consulting service at $100 hourly to the sales price, it Calculates:
Contract Term (# of Months) : 12 Months 
Monthly Subscription Cost: $101.00 Monthly (opp product Sales Price)
Total Product Quantity: 1,000   (opp product quantity)
1,212,000 Annually (Contract Term * Monthly Subscription * Total Quantity)
Is there a way to write a roll up summary to only add up or not add up product SKUs?