iPod/iTunes Annoyance

Apologies if someone's posted a thread like this before - I couldn't find any that had been.

Basically, whenever I import a load of songs by the same artist into iTunes, I filter though all of them making sure they have the same artist title, proper album name, a blank 'year' box etc. etc., the end result basically being they are fit to be put onto the iPod.
Despite this, after putting them onto the Pod, I get numerous duplicate entries when I scroll down the artist list e.g. If I put 6 songs by artist X onto the Pod, there will be 2 headers reading 'Artist X' and one will have 4 songs and the other will have 2, as opposed to the expected outcome of one 'Artist X' header containing the 6 songs by that artist.

Hope that made sense, I'll rephrase if it didn't. Anyone else had this? Can anyone remedy the situation?

Are they part of two different albums by that artist?

Sometimes are, sometimes not. Both my 'Dare' and 'Feel Good Inc' by Gorillaz share the same artist title, same album title and all other fields (year, genre etc.) are blank - yet they split up into two 'Gorillaz' headers.

EDIT: - Problem solved. Feel free to close.