When exporting Estimates from LMN to Quickbooks, your Costs will now be included on Estimates!
Access the QB Sync Tool > 3. Choose your import Settings
Under Costs and Prices, select Import Estimates with both Costs and Prices (Costs and Prices).
Now your Estimates will populate into Quickbooks to include your Costs.
Note: QB Desktop users, you will need to update your QB Sync Tool to the latest version (v18.104.22.168)