Best way to update dynamic records

I have a Budget program written in VB6 and it writes to an Access database using ADO.

A little background... It is for a commercial real estate firm. The budget uses projected income and expenses from each current tenant and the probability of a vacant space being leased within the lease term etc. There are multiple complicated calculations in relation to forecasting operating expenses and real estate tax escalations.

The user clicks a drop down and selects one of the accounts with the complex calculation. For each account, it takes the revenue of each tenant and calculates out each month. The is one row of data for each tenant and spec tenant. Depending on the tenant data when updated, the actual tenants could be different causing some records to need to be deleted instead of updated. I have the program first deleting all the records in the table and then adding it as new once calculated. I am doing it this way because I can't think of an easier way to update the table that would allow for the dynamics of the tenants.

For example, the data could look like this...

Old Data New Data
Tenant 1 Tenant 1
Tenant 3 Tenant 5
Tenant 5 Tenant 8
Tenant 8 Tenant 9

Therefore, when updating the new data, Tenant 3 should be deleted and Tenant 9 should be added.

I hope this makes sense....

Any thoughts are welcome.

Thanks!

Chrissy