As mentioned in the documentation, there are specific variants of the decimal-related tokens that output in an invariant-culture format (I.E. with a period as the decimal separator)
Internally, there are no actual periods or commas in use when storing the value in memory, but as soon as the value is converted to text, as is done by the tokens, the culture settings of your system (Windows) determine which character is used.
VoiceAttack is standardized, like many applications and programming languages, on using a period as a decimal separator for international compatibility when converting text to numeric values.
So when you use the regular "{DEC:}" token, and the output uses a comma as the decimal separator, that will be interpreted as a thousands separator (E.G. as in "1,000,000" for one million), and the leading zero will be dropped as it has no place in an integer number.
If you use "{DECINV:}" instead, the text value will not use your system culture settings, but rather a culture not tied to any specific country or region (the invariant culture) which will use a period as the decimal separator, and commas as the thousands separators.
All of that is moot (irrelevant) in this case, however, as you don't need a conversion at all; the value is already stored in memory as a number.
Instead of using a token, input the actual variable name into the "Another Variable" field.