For calculating shipping cost into the Google checkout, when you integrate Google checkout with Magento there is a folder installed named Shipping inside it. So, you can configure the second module called Carrier Calculated which help you count the shipping cost for the particular product based on the weight.
I’m having similar issues, using Magento CE 1.7.0 and Google Checkout. Using table rates for UK / European shipments. For UK orders the correct shipping value is shown by Google however for any European customers it shows the UK rate or no value at all.
I’ve got no errors shown in ‘Integration Console’ on the Google Checkout website and nothing in the Google error logs in var/log. I’ve had orders come through fine from UK customers and everything seems to be updating itself correctly with callbacks.
I have had a real good look at other threads / post here but nothing has fixed the problems.
I am running 1.7.2 and my shipping options weren’t transferring over to google checkout. I setup default shipping rates in google checkout itself and then disabled the sending of shipping options per the blog post above and it is working correctly now. Just need to remember if you change your shipping rates to also change them in google checkout. I use zone tables FYI, so it was easy for me to copy my rates from magento to google checkout admin.
Not sure why Magento doesn’t offer a simple option to disable shipping sending and to use google defaults.
I have no more experience but I have share some information with you .You’re solely responsible for specifying your own shipping rates. Google won’t apply shipping charges to your orders if you don’t specify any shipping information. Please also keep in mind that at this time, you may send all items within an order only to a single address.