25 October 2019
correct, this behavior has been standard for the simple reason that the unique counter has meaning when the file already exists and it starts counting to avoid to overwrite it.
However if you use the latest internal build available additional parameters have been added to the variable so that you can also customize this option, the counter now works like below:
%UNIQUECOUNTER% = initially not existing when file doesn't exist
%UNIQUECOUNTER3% = initially not existing when file doesn't exist, it is formatted by x (3) digits (e.g. 000)
%UNIQUECOUNTER3+7% = initially not existing when file doesn't exist, it is formatted by x (3) digits and starting from y (7) (e.g. 007)
%UNIQUECOUNTER3+7I% = (Inclusive) same as before but initially inclusive (so first file it will come directly with 007 rather than empty) -> this is your case
%UNIQUECOUNTER3+7+_% = existing or not initially according the usage of I which can be added or not but using the _ character as separation from the previous filename (e.g. _007). This is for cases when you don't want the extra char when the counter isn't used (example without I so counter not used initially) because if you put the _ in the filename then the initially filename will just end in _ being without the counter.