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I had my battery replaced by Apple early Feb. 2021 in a 2015 MBP 15". The cost was $199 for the battery/top case plus $19.95 for a Portable Shipping Charge for a total of 218.95. The difference from $199 to $259 might be for shipping/handling.

I suggest you contact Apple Support and ask them.
 
Still shows as $199 for MBP 16:


Where do you see $259?
A google result gave me this link


apparently this is canadian upon looking closely
 
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