THE separation of China and public relations business from the 1992 4As Agency Hongkong Income Report seems to have had remarkably little effect on advertising industry capitalised billings and income compared to 1991. Measuring all income except China and public relations, the industry experienced 12 per cent growth last year to reach a record total income of $927 million. If the estimated $500 million income for China and public relations is added to this, the figure increases to 14 per cent. This year marks the first time advertising agencies have all been measured from the same base; that is all billings except those from public relations and China business. As in 1991, if inflation is taken into account, real growth is almost zero. But agency managing directors remain happy at what has been a 12-month consolidation period rather than a period of rapid expansion. ''Spending was very conservative up until the last quarter of 1992 because people were feeling very uncertain about the economy,'' said Mr Jeffrey Yu, managing director of BSB. ''Growth from existing clients wasn't very big. Many of them held back on expenditure until they felt surer about the economy.'' BSB dropped three places in the rankings to number 10 and saw billings decrease by eight per cent to $354 million. This was largely because of the loss of the regional De Beers business to J Walter Thompson (JWT) at the end of 1991. But last year BSB regained billings by winning Malaysian Airlines System, and has since won Taj Mahal hotels, Kowloon Dairy and Henry Jewellery. ''We are not unhappy with our position because we've had a good comeback since De Beers' loss and have recovered most of the billings,'' Mr Yu said. ''We want to be a medium-sized agency doing good work and that is what we are.'' The list of the top five agencies has completely changed from 1991, with former number one Leo Burnett slipping to fourth place and handing over the mantle of top Hongkong agency to JWT. JWT outstripped its former rival by $143 million and notched up a 17 per cent growth in billings from $551 million in 1991 to $644 last year. Leo Burnett lost $135 million for its China business and, because of this, saw billings decrease by 14 per cent to $501 million. As expected, DDB Needham entered the top three for the first time, reaching number two with billings of $631 million, a 41 per cent increase over 1991. ''We are very proud of our achievement in the last three years. Our three-year plan was to take DDB into the top three agencies and we have done better than that,'' said Mr Aaron Lau, deputy managing director of DDB. ''Most of the growth was from existing clients and additional assignments. ''What we want to do now is focus on our clients and our people, giving our clients the best service available and training and developing our own staff.'' Three years ago, DDB's capitalised billings were $294 million. Since then, the addition of clients including STAR TV, Park 'N Shop, Audi Volkswagen, Jardine Office Systems and Apple Computers has seen its billings rise to $446 million in 1991 and a total of $631 million last year. Growth among the other 4As agencies varied. Ogilvy & Mather's billings grew two per cent to $598 million, $33 million behind DDB. Dentsu, Young & Rubicam and Ball Euro RSCG both saw billings decline, while DMB & B, Grey, Bozell and Saatchi experienced increases of 10, 13, 17 and 17 per cent respectively. Some agencies, particularly those with substantial China business, were disgruntled over the release of advertising income some weeks before figures for income from China were due to be issued, saying it gave a false impression of industry growth. ''If you analyse 4As agency income over the past three years it is probably fair to say that incremental growth has come out of China,'' said one industry source. ''Growth in Hongkong in recent years against a small population has been quite limited and any increase has been largely fuelled by offshore billings,'' he said. China billings figures will be released by the 4As later this month.