dpkg-shlibdeps libstdc++6 instead of libstdc++6:i386

bfile is ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.2.0

ldd ./bfile | grep libstdc++.so.6
        libstdc++.so.6 => /usr/lib/i386-linux-gnu/libstdc++.so.6 (0xf762c000)

dpkg -S /usr/lib/i386-linux-gnu/libstdc++.so.6
libstdc++6:i386: /usr/lib/i386-linux-gnu/libstdc++.so.6

but in genereted depends we see libstdc++6 instead of libstdc++6:i386:

dpkg-shlibdeps ./bfile -O
shlibs:Depends=lib32gcc1 (>= 1:4.1.1), libc6-i386 (>= 2.1.3), libstdc++6 (>= 4.1.1)