You can decide whether you'd like to show a full breakdown of services or a total only on the invoice from your Xero settings.
How To Change The Settings
Step 1. Head to Settings > Integrations > Xero or Quickbooks (respectively)
Step 2. Choose your preferred fee display settings from the drop down
On this page, there is a field titled how to show line item pricing. You can choose between a full breakdown or total fee from the dropdown in this field.
Step 3. Save your settings.
This won't effect the fee display in your proposals, which you can still show as a breakdown or total regardless of your invoice preferences.