Sharsies and Corporate Bonds

[Beagle]

One thing that's got under my skin a bit is the brokerage rate on corporate bonds traded on the NZDX. Now that some decent bonds are back to trading on a yield to maturity of ~ 5% and the outlook in market for shares is pretty difficult I reckon bonds are starting to look like a fairly attractive asset class for some of one's investment portfolio, (after starting the year with the worst losses in capital value in decades).

Bonds are traded on the NZX just like shares I struggle to accept why the brokerage rate on these should be different to the 0.2% on shares through Direct Broking / Jarden Direct, pricing for bonds is here https://www.jardendirect.co.nz/pricing
To add insult to injury they charge you the $5.50 trade fee on top of their 0.5% brokerage for under $50K of bonds which is 2 1/2 times their brokerage on shares yet these are all executed electronically on the NZX ?

I looked on Sharsies website but couldn't see any pricing for corporate bonds, anyone know if bonds are priced differently to their 0.1% brokerage on shares on that platform ?