The company said the difference of $49.7 million in its EBITDA from 2017 could not be taken as providing a correct picture of its financial status.
It said the FY18 EBITDA result did not include an material irregular items and was representative of the underlying EBITDA for the period.
"By contrast, as reported last year, the FY17 EBITDA result benefitted from $55.8 million of favourable non-recurring items (predominantly a profit realised on sale of an investment)," TPG said.
Last month, TPG announced a merger with Vodafone Hutchison Australia which would create a company with an enterprise value of about $15 billion.
It said 50.1% of the merged entity would be owned by Vodafone with the remainder to be owned by TPG.
TPG said it had net debt of $1.27 billion at the end of the 2018 year, a leverage ratio of about 1.5 times EBITDA. It also had undrawn headroom of more than $1 billion in its debt facilities to find the balance of its planned mobile network in Australia and Singapore.
The company said the NBN would continue to affect earnings in the year ahead, as both DSL services and home phone services continued to migrate to the broadband network. It said there would be also be an impact by adoption of the new AASB15 rec=venue accounting standard.