Hi is it possible to customise summary

Not at this time, it has been a wish of a lot of people based on SuiteIdeas,

You can with a script

I've done it by using CMS HTML content in SMT and adding javascript on checkout pages or all pages, that messes with the HTML on the page using setInterval and jQuery inside a script tag. That's probably the dirtiest way to do it that is not future proof, so I'd like to hear your method, @Tim Chapman I've already had a couple of things break doing it my clunky way when NetSuite updates their suitecommerce Theme we're using.

I guess to my understanding this was the summary box on a transaction in NetSuite, not a check out screen via SuiteCommerce

Oh! You're right, @Tim Chapman. I didn't realize that's what I was looking at in the screenshot 🙂 In that case, yes I think you'll need some client scripting if you want to update it interactively and not just on record load. And if you want to change the look or contents of the box and not just how it adds up the numbers, you'll need either a non-stored Inline HTML field or a User Event script beforeLoad function that creates one. From there you'll need to decide if you're going to override the existing functionality and contents or replace it with your own summary box. Update the contents on fieldChange and that function that gets triggered by sourcing (I forgot the name). Those seem to always trigger when something that would affect the totals happens.

We are using the User Event script beforeLoad