Really confused about upgrade fees.

I am currently using a Samsung s8 on a post-paid unlimited plan. I would like to upgrade to a s10e.  I would prefer the Verizon version over the unlocked version to ensure that all of the advanced features work.    Best buy online is offering the Verizon 128gb s10e for $550 if I activate today and $450 if I activate later.  I would have thought it would be the other way around.  If I order the unactivated version, will Verizon charge me an upgrade fee to change over?  Does it matter if I use the new sim that comes with my phone vs using the sim from my old phone.  

Re: Really confused about upgrade fees.
Customer Service Rep

It is important to have the right information before making a decision to upgrade. Verizon Wireless is waiving upgrade fees for devices purchased via My Verizon online, the app, telesales, chat and Customer Service. However, this does not apply to national retailers such as Best Buy. The device is currently priced at $599 through our website.