I think you should set this up as a related table of expense entries with fields to record the description, the amount and the selected account number. A summary report based on this table, but drawing data about the conference from the related conference record can be designed that groups your expenses by account and computes a subtotal for each.
Conferences::ConferenceID = Expenses::ConferenceID (Conferences::ConferenceID should be an auto-entered serial number).
Define these fields in Expenses:
Description (where you enter Honorarium, travel, etc.)
sTotal (a summary field defined as the Total of Amount )
You'd place a portal to Expenses on your Conferences Layout and format the Description and Account fields with drop down lists to reduce data-entry errors.
You can then either use relationships that report a total for each specified account on your conferences layout, or you can place a button on your conferences layout that pulls up this same set of records in a summary report based on your Expenses table that looks like this:
Conference Name, date, etc. (any fields from the conferences table that you want at the top of your report)
Total for 43100: $700
Total for 44100 $375
Grand Total $1075
This portal with summary report based approach will enable you to process very different expense reports without having to redesign your system.
Thank you for your suggestion for how to structure the database. I will try to implement the changes and see if any questions arise.