I remember vaguely that in many episodes whenever Sundar came Champak went missing.
For example, During one water shortage epi. when Sundar came with a Van full of pilgrims from A'bad to Shirdi, Champak was nowhere to be found.
In the Red-cherry mobile episode, Champak leaves for Yaatra. But it was demanded by the story (otherwise the misunderstanding plot, couldn't develop)
Can you recall anymore episodes when Sundar came but Champak was absent? And can you speculate any reason for it, other than the one given by the scriptwriter (i.e. yaatra or temple visit)?
May be because they cannot stand the sight of each other. May be Champak is overworked so he takes holiday or may be director is doing it to save budget by not having to pay so many characters.