I'm using the multibib package to distinguish different types of references. In my document I have about 50 references in the first and about 70 in the second reference list. The numbering of the references works fine, but the formatting changes with reference number 100. I have created an MWE that isolates the main issue: the maximum label length seems to extracted by the number of elements of just one reference list.
In this example everything works fine, because i have 100 references in the second reference file:
\documentclass[12pt]{scrbook}
\usepackage{cite}
\usepackage{multibib}
\usepackage[fixlanguage]{babelbib}
\usepackage[german]{babel}
\selectbiblanguage{german}
\newcites{mine}{FooBar}
\begin{document}
\citemine{A1}
\cite{A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,A30,A31,A32,A33,A34,A35,A36,A37,A38,A39,A40,A41,A42,A43,A44,A45,A46,A47,A48,A49,A50,A51,A52,A53,A54,A55,A56,A57,A58,A59,A60,A61,A62,A63,A64,A65,A66,A67,A68,A69,A70,A71,A72,A73,A74,A75,A76,A77,A78,A79,A80,A81,A82,A83,A84,A85,A86,A87,A88,A89,A90,A91,A92,A93,A94,A95,A96,A97,A98,A99,A100}
\bibliographystylemine{babplain-Customized}
\bibliographymine{references}
\bibliographystyle{babplain-Customized}
\bibliography{references}
\end{document}
The result looks like 
In this example I have an issue, because i have less than 100 references in the second reference file:
\documentclass[12pt]{scrbook}
\usepackage{cite}
\usepackage{multibib}
\usepackage[fixlanguage]{babelbib}
\usepackage[german]{babel}
\selectbiblanguage{german}
\newcites{mine}{FooBar}
\begin{document}
\citemine{A1}
\cite{A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,A30,A31,A32,A33,A34,A35,A36,A37,A38,A39,A40,A41,A42,A43,A44,A45,A46,A47,A48,A49,A50,A51,A52,A53,A54,A55,A56,A57,A58,A59,A60,A61,A62,A63,A64,A65,A66,A67,A68,A69,A70,A71,A72,A73,A74,A75,A76,A77,A78,A79,A80,A81,A82,A83,A84,A85,A86,A87,A88,A89,A90,A91,A92,A93,A94,A95,A96,A97,A98,A99,A100}
\bibliographystylemine{babplain-Customized}
\bibliographymine{references}
\bibliographystyle{babplain-Customized}
\bibliography{references}
\end{document}
The result looks like 
My aux files look good and as far as I understand the bst file I would expect that the longest label, i.e. 100 would be identified. But from the MWE it follows that the entries seem to be counted to determine the longest label.
Has anyone an idea how to trick bibtex to get a nice and clean formatting of my reference list?
You'll find the bst file here
You'll find the reference file here