In Rollins v. Commonwealth, 37 Va. App. 73, 554 S.E.2d 99 (2001), Rollins argued, like Hegedus, that the operator's failure to conduct the validation test of the Intoxilyzer 5000 machine immediately after the breath analysis, as specifically required by 1 VAC 30-50-90(C), rendered the certificate of breath analysis inadmissible. The Court held, however, that, because the breath-test methods set forth by the Department of Criminal Justice Services, Division of Forensic Science in 1 VAC 30-50-90 were procedural, rather than substantive, in nature, substantial, rather than strict, compliance with those methods was sufficient. Id. at 79, 554 S.E.2d at 101. The Court further concluded that the trial court properly admitted the certificate of breath analysis into evidence, because the Intoxilyzer 5000 machine operator in that case, "having administered the breath-analysis test to Rollins in accordance with 1 VAC 30-50-90(A), substantially complied with the breath-test methods approved by the Department of Criminal Justice Services, Division of Forensic Science." Id. at 82, 554 S.E.2d at 104.