Hi Steve,
We have requested the same issue resolution previously, so hopefully your request gets added to ours.
If you can resolve with 4 decimals in IC, you can use alternate pricelists (IC) enabled in Purchase Orders, with the unit price set to 4 decimals.
The Markup cost on the Alternate Price List is the the purchase unit price, and you set the 4 decimals on the second screen. To use, you can set the Price List on the Vendor Record.
For actual 4 digit inquiries of item costs, we use Gridview,
We'll use this configuration for many sites needing 4 decimals for the unit price.
Best,
Brian