updating php5 metapackage brings in unnecessarily libapache2-mod-php5

I have a system with the following packages installed:

ii php5 5.5.9+dfsg-1ubuntu4 all server-side, HTML-embedded scripting language (metapackage)
ii php5-cgi 5.5.9+dfsg-1ubuntu4 amd64 server-side, HTML-embedded scripting language (CGI binary)
ii php5-common 5.5.9+dfsg-1ubuntu4 amd64 Common files for packages built from the php5 source
ii php5-gd 5.5.9+dfsg-1ubuntu4 amd64 GD module for php5
ii php5-json 1.3.2-2build1 amd64 JSON module for php5
ii php5-mysql 5.5.9+dfsg-1ubuntu4 amd64 MySQL module for php5

If I attempt to update these, libapache2-mod-php5 gets pulled in as a dependency although the installed php5-cgi should be sufficient to satisfy the dependency requirements of php5:

The following NEW packages will be installed:
   libapache2-mod-php5 (5.5.9+dfsg-1ubuntu4.1)
   php5-cli (5.5.9+dfsg-1ubuntu4.1)
   php5-readline (5.5.9+dfsg-1ubuntu4.1)
The following packages will be upgraded:
   php5 (5.5.9+dfsg-1ubuntu4 => 5.5.9+dfsg-1ubuntu4.1)
   php5-cgi (5.5.9+dfsg-1ubuntu4 => 5.5.9+dfsg-1ubuntu4.1)
   php5-common (5.5.9+dfsg-1ubuntu4 => 5.5.9+dfsg-1ubuntu4.1)
   php5-gd (5.5.9+dfsg-1ubuntu4 => 5.5.9+dfsg-1ubuntu4.1)
   php5-mysql (5.5.9+dfsg-1ubuntu4 => 5.5.9+dfsg-1ubuntu4.1)

If I update the php5-* packages first and then attempt to update php5 everything works as expected.

Is this a bug or a feature?