Number.ToText Works in one table but not another

I am concatenating two numbers and adding leading zeros to one. I used;

Number.ToText([orderno])&"-"&Number.ToText([ordersuf],"00") in One table and it worked.

In the other table it only returns the end numbe without the leading zero. 

I have tried formatting the columns to text etc and nothing works. Any hints as to what nis going on? Have another formula for this?

Thank you.