I understand the importance of having a "Select All" option when adding the billable time in the invoice, @cbarnes4. Let me share some information about this matter. 

The "Select All" option to add the billable hours from the suggested transaction in the invoice is currently unavailable in QuickBooks Online, and you'll need to add it manually to the invoice. With this, I recommend sending a feature request to our Product Development team to consider and add this for future product updates. 

Here's how:

1. Select the Gear icon, then choose Feedback.
2. Type in your comments or product suggestions.
3. Select Next to submit.

On the other hand, I have another option that you can do to add all the billable hours in one go. You can follow the steps below for your guidance:

1. Go to Sales, then select All Sales.
2. In the Transaction type dropdown, select Unbilled Income.
3. Select the time charges or billable hours related to the project or customer or click the box beside the Date column to select all.
4. Click on the Batch actions dropdown, then select Convert to Invoice.
5. Review the invoice, then once done, click the Review and Send or Save and Close.

Additionally, once your customer pays the invoice you sent, you can record it to connect it with the invoice and mark it as paid. 

Let me know if you have other questions about managing billable hours in invoices or have any concerns about QuickBooks. I'm just a click away and ready to help you. Have a wonderful day!