Stats Dashboard Sales total very different to Stats-Sales & Orders - Why?

[ukbaz]

Using Prestashop 1.6.1.16 and am experiencing an issue with getting valid sales figures...

I know in the Dashboard total sales exclude VAT and in Stats, Sales & Orc=ders the amounts include VAT

However, even taking that into account there is still a discrepancy between the two figures!

 

For example:

Dashboard sales for 01/05/18-31/05/18 =£34,221.85

Add VAT @20% total should be: £41,066.22

Stats-> Sales & Orders for 01/05/18-31/05/18 shows total as £38,565.39.

That's a big difference!

Where is the difference coming from - and which figure is correct??

 

Thanks

Baz