A goof up by companies in filing corporate tax after the introduction of a single challan system depressed the collection figures and irked the finance ministry, which was fast to detect the mistake running into Rs 6,120 crore.The ministry scrutinised the figures as it was intrigued by the sluggish 5.6 per cent growth in corporate tax mop-up despite an impressive industrial growth and hefty profits netted by India Inc.The goof up occured as many companies by mistake ticked income tax instead of corporate tax in the single challan system introduced this year for both income and corporate taxes, official sources said here on Friday.The finance ministry was fast to correct the figures and corporate tax collections now showed Rs 26,223 crore till September after Rs 6,120 crore, wrongly shown as accruals in income tax, was added to corporate tax kitty.The correction ensured that corporate tax growth was a robust 38 per cent instead of the subnormally low 5.6 per cent in the first half of this fiscal.The correction, however, brought down the income tax figures which had earlier shown an astronomical growth of 74 per cent at Rs 25,117 crore or Rs 6,120 crore higher than the actual figure.