Trustpower then filed court action in 2011 against Inland Revenue and Justice Pamela Andrews found in favour of the electricity company in a decision released last November.
The two sides then squared off over costs.
IRD accepted liability and paid Trustpower $639,967. That was made up of $477,290 in costs and $162,677 in disbursements.
Trustpower, however, believed it was entitled to a total of $1.45 million and argued this before Justice Andrews earlier this year.
Although Trustpower didn't get everything it was asking for, Justice Andrews this month said the IRD was to pay the company additional costs.
Trustpower spokesman Graeme Purches said the judgment meant the total amount the company got in costs was just over $1.1 million.
He also mentioned, however, that IRD had appealed the original decision that fell in Trustpower's favour and that challenge was due to be heard next March.
Read the full decision here: