Company DC (aka 401k)

[Ori]

So I'm enrolled in our company DC with matching, meaning I cannot use iDeco (unless I quit DC).
We can choose from limited list of funds (basically, one funds per each asset category), and they are quite expensive, much more expensive than Tawara or Nissei.
When I approached our HR about this, they told me that they only can (allowed?) to choose from the list of funds which are approved (by Kinyuchou?). This list of funds to choose from is provided by banks (UFJ in our case) and they chose the cheapest ones from the list (they showed the list to me). They also told me they would be happy to add cheaper funds, but they don't think that there are any such funds which are approved for DC.

Does anyone know how this whole system works and if cheap funds like Tawara, Nissei or eMaxis slim can be used in company DC?

P.S. I'm not sure if this topic should go here, or to iDeco board...

[RetireJapan]

Think iDeCo is slightly better fit