I'm not familiar with the rod you mention, however, a few things to keep in mind. D1.1 (2006)
1.2 Limitations
The code is not intended to be used for the following:
(1) steels with a minimum specified yield strength greater than 100ksi.
(4) base metals other than carbon or low-alloy steels.
also, if your welders are qualified to an F4 group using 7018, and the rod you mention is in an F8 category, then your welders wouldn't be qualified. Take a look at table 4.12(2)
I don't have D1.5 book on hand, so I can't say whether or not that code has limitations.
If I'm missing something, someone please let me know.
Jason