If you have several batches of ESS shares, divide the quantities...

If you have several batches of ESS shares, divide the quantities of each batch by 6.18 and round to get the equivalent number of DVP shares per batch. If the overall totals of these calculated values is different (it will only be by one or two) to the value of DVP shares you received according to your statement last week (or what was added to your broker account), you may have to adjust one or more of the DVP batch quantities by +/- 1 to get them the same. This difference is because your allocation according to the statement is based on dividing your total ESS holding by 6.18 and rounding, whereas this may not work out exactly the same when the allocation is worked out at the individual batch level.

Once you are happy with the individual batch quantities, then you can work out how much each allocated DVP share "cost" by dividing the value of each batch by the quantity of DVP in the batch. I tend to keep the commission separate, so the commission will be the same as for the original batch, except the unit price is different.

For instance, if one batch was:

28-Feb-23 618 ESS @ $0.50 = $309 + $20 commission = $329, that becomes
28-Feb-23 100 DVP @ $3.09 = $309 + $20 commission = $329.

The purchase date is the date when you bought that batch of ESS.

So when you sell the acquired DVP, just use the second line as your cost base. Keep your ESS records as you will need them to justify your calculations above.