Hi Gene,
for the first issue I would use a custom template for Kindle book that does not have price information as this is not supported by Amazon yet.
For issue two you could use the new placeholder {$OffersMainPriceAmount} to only use the Amazon main price. Check the end of the placeholder list for more details: http://www.wp-amazon-plugin.com/placeholders/
I hope I was able to help you. If you still have questions, please let me know.