The regulator caused uproar in March from the likes of the British Heart Foundation, consumers' group Which and the National Union of Teachers, who demanded to know why its proposed crackdown on food advertising to children did not include a complete ban on advertising of high fat, salt or sugar (HFSS) foods before 9pm.
Last Thursday, the regulator issued a revised consultation document and announced it was extending the deadline for responses, initially set for last week, until 30 June.
In the revised document, Ofcom admits Food Standards Agency figures suggest the health benefits of a watershed could be anything between £250m to £990m a year, by removing 82% of impacts for HFSS foods for children aged four to 15.
However, Ofcom says the cost to UK broadcasters could be greater than the estimated immediate advertising loss of up to £175m a year.
The document says: "A pre-9pm ban, rather than being targeted at younger children, would prevent adults from viewing advertisements for most HFSS food and drink products aimed at them.
"As a result, it could make television an unattractive medium for food and drink advertisers; it may, for example, be uneconomic to produce television advertisements if they can only be shown after 9pm."
Broadcasters welcomed Ofcom's move, but a spokesman for the British Heart Foundation said Ofcom's statement would not stop the health lobby pushing for the watershed, claiming it had the backing of nearly 70% of parents and 250 Labour MPs.
Ofcom's proposals includes options for a crackdown based on just high fat and sugar foods, a ban of all food advertising shown in programmes aimed at children, or introducing limited amounts of food advertising aimed at children. In its revised document, Ofcom admits that even a ban on only HFSS foods would cost children's channels more than 4% of their annual revenue on average, with the figure much higher for some.