Application vs Bio-Metric Timeline

[smithy101]

I paid for the priority service and I am just wondering, in respect of timelines, is the wait calculated from date of application or bio-metrics. I have noticed people on here count from bio-metrics however, just noticed the following in my email from Sheffield.

"If you have paid for Priority Service we aim to complete your application within 6 weeks of your submission date".

A little confused here! Can someone please clarify ..

[seagul]

More likely it starts from the time when they receive your supporting documents and mostly they receive them on the day of biometrics.