I was informed recently that perhaps trying the 2.0.7c version of VM (in beta) might solve this problem.
I haven't been able to get it to work, myself.
J 2.5.4/ VM 2.0.7c (doesn't work in 2.0.6)
Still in limbo... client frying because they're not making money online (their main income) through the inability to satisfy wholesale clients.
I've been trying any work-around for a few weeks to no avail. Client doesn't want double products to have to admin'... there are a lot of products.
Really hoping the team can pull together the final piece of code that does something like tie the created 'shopper group' to the 'calculated results', having the results actually 'showing' for each shopper group when they're logged in - and that all shopper group calculations/results become a real conversion at checkout. ie: No point being logged in as a wholesaler if they can't get the discount. 
I don't sweat it often... but if I'm asked to find an alternative for a platform that has served so well up until this recent... sorry, have to call it an 'issue'... I have no idea what this lady will be able to use to replace VM.
Go "The Team"!... you can do it! (*anxiously dabs brow
)
If anyone has any suggestions... feel free.
I was informed recently that perhaps trying the 2.0.7c version of VM (in beta) might solve this problem.
It works!
J 2.5.4/ VM 2.0.7c I'm working with "%" discount, so this is how it worked for me.
Create shopper group: Add your shopper group name and description (don't forget to publish)
In Show Following prices, I have ticked
- Enable shoppergroup specific price display & Show Prices
and the following Show Price & Show Label boxes:
- Baseprice with Tax, but without discounts, Discounted Price without tax, Final salesprice, Tax amount
(Your choices may be different)
SAVE
Create shopper group calculations:Go to Products > Tax & Calculation Rule Details
Add Name/ Rule - and select 'Price modifier before tax' as the Type of Arithmetic Operation
Math Operation: -%
Value: 50.0000 (eg.)
Currency: Select you own
Product Category: We selected all.
Shopper Group: Your selection from the Shopper Group you already created ( )
Country: Obvious
State/Region: Obvious
Visible for Shopper: yes
Visible for Vendor: yes
Start date: yesterday
End date: never
Vendor: Yours
Publish and Save.
Go to your Products and edit each product.
In Product Information, look for 'Pricing rules overrides' and click inside the 'Discount Type' input box to select your Shopper Group which should be visible if you've created it and published it.
Check the front end as a general registered user, as well as a 'shopper group' user to see the results.
You can take it from there.

I hope this helps someone else.
Cheers... off to update some products
EDIT: Back again. Nearly... Not quite. After logging in as a registered user in the default group, the discount allocated for the other shopper group is given at 'add to cart'.
The 'discount type' on the product works across the board - you're not able to differentiate between the shopper groups.
A couple of additional options required here unless someone can explain it.
If you work this one out, or have an answer... can you get back to me?

Thanks