Can InvoicedQuantity be an integer

XML and business rules
1

I’ve noticed in a sample invoice that the InvoicedQuantity = 2.000000

Is it allowed that I can place just an integer like 2?

Here’s the line:

<cbc:InvoicedQuantity unitCode="PCE">2.000000</cbc:InvoicedQuantity>

Also I’d like to know the meaning of PCE in unitCode and other available unitCodes