The actual tax due is calculated at final disposal. It is the encashment value less premiums paid and is zeroised if negative. Note any tax paid on DD is added back in this calculation.
Taxes paid at deemed disposal are just down payments.
If the amount paid on deemed disposal(s) exceeds the amount due on final disposal it is refunded but not exceeding the final amount due.
Example: tax on DD €10k. Final position a loss of, say, 5k. Final tax calculation 0; refund €10k.
Note that the actual tax rate that matters is the one at final disposal. Example:
Gain at DD €10,000; Exit Tax rate 41%; down payment €4.1k. Gain on final disposal €15k; ET rate 33%. ET due €5k less €4.1k refund.
Hence if you believe ET rate has more chance of falling in future than rising (which I do) you should let the DD take place and not encash and reinvest but of course vice versa if you think the rate will go up.
@Corola's calculation works if the Exit Tax rate stays the same but is incorrect if it changes, thus:
Case 1
Year 10:
€143,600 = 883 units at €162.65 each
Gain = 883 * (162.65-100) = €55,314
Assume Exit Tax rate falls to 30%.
Tax = €55,314 * 30% = €16,594
Credit tax already paid in year 8 = (883/1,000) * €16,400 = €14,479
Amount to pay = €16,594 - €14,479 =
€2,115
Correct calculation:
Final taxable gain: €143,600 + €16,400 - €100,000 = €60,000
Tax = €60,000 * 30% = €18,000
Credit for down payment of tax in year 8 €16,400
Amount to pay = €18,000 - €16,400 =
€1,600
@Corola is assuming that Deemed Disposal is a "reset" whereas it is merely a down payment on the final tax due.
At least that is my understanding but I stand to be ejected.