The survey found 17 per cent have seen over-servicing levels increase during the first quarter of this year as opposed to 11 per cent seeing them decrease, while 67 per cent said they were unchanged.
However, the trend was less pronounced than in the final quarter of 2013, when 37 per cent reported increasing over-servicing.
PRCA director-general Francis Ingham said that this levelling-off, along with other positive findings in the survey, meant there was "much to feel confident about".
The survey found that 80 per cent of agencies described new business as either busy or very busy in the first quarter of 2014 – a rise from 76 per cent in the final quarter of last year and the highest reading since the final quarter of 2012.
More than half of agency heads (57 per cent) said they felt optimistic about their consultancy, though only 38 per cent said they felt more optimistic about the PR industry in general.
In addition, 71 per cent of agency owners believed that the UK economy would improve in the next 12 months and 49 per cent expected staff numbers to increase in the next quarter.
New business was coming primarily from new clients rather than existing clients, according to 56 per cent of consultancies.
The survey drew responses from 46 agencies.