Master's 10% Best Price Guarantee

I just want to know if Masters have done the right thing. I purchased a new fridge the other day from Masters. I asked them to price beat an identical product offered by another retailer which was selling it for considerably cheaper. The competitor's shipping fee was about $50. When the price beat was initiated, Masters took into account the cost of shipping that was charged by the competitor. They then took 10% off the grand total price (fridge plus shipping) of the competitor. After the discount was applied, Masters then added the cost of their own shipping which was around $70. So in the end, I was only going to save about $4 by going through with the price beat. What I want to know is, why does Masters add the price of shipping from the competitor if they're going to add their own shipping charges (which is not subject to a discount)? Am I missing something here? Thanks.