[OMPI users] Why are the static libs different if compiled with or without dynamic switch?

[twurgl]

I am setting up Openmpi 1.8.4.  The first time I compiled, I had the following:

version=1.8.4.I1404211913
./configure \
    --disable-vt \
    --prefix=/apps/share/openmpi/$version \
    --disable-shared \
    --enable-static \
    --with-verbs \
    --enable-mpirun-prefix-by-default \
    --with-memory-manager=none \
    --with-hwloc \
    --with-lsf=/apps/share/LSF/9.1.3/9.1 \
    --with-lsf-libdir=/apps/share/LSF/9.1.3/9.1/linux2.6-glibc2.3-x86_64/lib \
    --with-wrapper-cflags="-shared-intel" \
    --with-wrapper-cxxflags="-shared-intel" \
    --with-wrapper-ldflags="-shared-intel" \
    --with-wrapper-fcflags="-shared-intel" \
    --enable-mpi-ext

And when installed I get (as a sample): 

  -rw-r--r-- 1 tommy 460g3 6881702 Feb 19 14:58 libmpi.a

Now the second time I install, I had the same as above for the configure, but
this time I took out the "--disable-shared" option.

and again, as a sample 

  -rw-r--r-- 1 tommy 460g3 6641598 Feb 24 13:53 libmpi.a

Can someone tell me why the static libs are different (sizes) when compiling or
not compiling the dynamic ones?  Seems to me that static ones should be
identical.  Is this an issue?

thanks for any info