The Oracle: Publishing vs recording

A – Most record companies, both major and small, will have a publishing company that is affiliated with their record label. Examples of this are Warners/Chappell, EMI and Universal. It makes sense for them to operate this way, as they can have better control over all sources of income from your music and this should assist them in planning and organising your career.
So there is nothing intrinsically wrong with signing deals with two related companies nor is there any specific advantage or disadvantage in doing so. Just ensure that both contracts are viewed separately and negotiated separately.
Essentially the two contracts are for different uses and are with two different, albeit connected companies. Your publisher will supposedly find potential users for your music, issue them with licences, collect payment and then pay you, the writer of the music.
A good publisher will be creative by putting you together with other writers, helping you fine tune your writing and matching writers with artists etc. They can also use their clout to find you a record deal if you don’t have one already and will even promote your records after you have got a deal. Also it is important to check if your publisher is affiliated to any other publishers, record companies or territories.
A publisher may be affiliated with a major for the US market and have separate sub-publishing deals with other publishers for the rest of the world. Maybe they are not affiliated with anyone at all but are stand-alone operations.
Unless the latter have very good contacts, they may find it difficult to generate income from your publishing.
The difference between a good publisher and a bad publisher can definitely effect your wallet. A good one will know how much to charge for licences and know where to look for hidden monies, especially in foreign markets.
A bad publisher can lose you money by just sitting there and not doing anything. Also remember that a major publisher will have tens of thousands of copyrights so you can get shoved on the back shelf.
Nowadays, many writers decide to keep their own publishing. Well-established writers don’t need a publisher because people are regularly begging them for songs. Today it is more common for artists to write and record their own music. If you do decide to keep your own publishing, in time you may need to hire someone to administer your publishing for you as it gets to difficult to manage it yourself. Certainly if your music doesn’t lend itself to being recorded by other artists, such as jazz, rap or even heavy metal, then you should probably forget about looking for a publisher unless you want or need an advance up front.