Length of 'Invoice total' and 'VAT total'

I’m following the official E-invoicing-Detailed-Technical-Guideline.pdf

In page 60
VAT total
Tag:5
Length:45
Value:114.90
Hex:31 31 34 2e 39 30

Invoice total
Tag:4
Length:6
Value:1108.90
Hex:31 31 30 38 2e 39 30

How is the length calculated for these two tags?

Can I please receive help with this?