We would be grateful if when you create the invoice/estimate you select the customise option at the bottom of the page in the black area and select the template that you have created, then select print or preview.
When you created the invoice/estimate template which design have you selected within the custom form styles section, we are unable to tell this from the screenshot.
Select cog/gear icon > custom form styles > edit (the invoice you created) >design > change up the template.
When creating invoices from estimates (using the progress invoicing feature), the system is designed to default back to the Airy template - and so will not use your import form style. The workaround for this is to: open the Estimate and instead of converting it to an Invoice, mark the Estimate as Closed. You can then create the Invoice manually based on the info prefilled from the Estimate.