Yes, but there's an obvious difference between:
00042
00043
00044
00046 (missing number precedes)
and:
20080501
20080502
20080503
20080512 (issued on the last day of May)
20080601
...
20090101
If one accepts that date-based invoice numbers are acceptable (and I
contend the taxman might do so), no-one expects to see invoice number
20081301, and the "gap" between 20080512 and 20080601 is quite
logical & reasonable. It's the anomalies that raise the taxman's
hackles, not the choice of implementation.