Max Number of Post Versions Supported

You should set WP_POST_REVISIONS to a fixed number. If you don’t, WordPress will keep an unlimited number of revisions. See function wp_revisions_to_keep():

function wp_revisions_to_keep( $post ) {
    $num = WP_POST_REVISIONS;

    if ( true === $num )
        $num = -1;
    else
        $num = intval( $num );

    if ( ! post_type_supports( $post->post_type, 'revisions' ) )
        $num = 0;

    return (int) apply_filters( 'wp_revisions_to_keep', $num, $post );
}

On the other hand … if you need such a high number of changes you should revisit the edit work flow. There are surely ways to get this number down.