Hi Patti,
Thanks for your post and welcome to the Community :)
The number format should always be set to 2 decimal points so this is unusual to hear.
Can I check when you are referring to the cost column, does this relate to the 'amount' column on the invoice/estimate?
Do you use one of the default product/service in the product/service column (e.g. Sales) or is this a custom product/service?
It may be worth checking this isn't relate to a cache issue by clearing the cache on the browser you are using here.
Thanks