Jianpu equal spacing

[Molbo]

Dear lilyponders

I am finally getting jianpu up and running. Thanks for all the help. I found a 
snippet and made a scoresheet with jianpu and found one problem. I will try to 
explain it as clearly as possible, but I don't know the technical terms so I 
will also give an example. 
The problem is as follows:
The spacing of "tempo" changes throughout the scoresheet, depending on how many 
numbers (in jianpu the notes are numbers) there are in a "tempo".
Example: | i 0 7. 6 | 5 5 6 5 5 6 | 5 - | 
They are all three of different lengths because they don't have the same amount 
of numbers. How can I make the spacing uniform throughout the scoresheet?

Best regards
Rene M