Steel roof deck failed inspection this morning. Looking for some engineering insight.

Okay, fair warning I used chat to summarize my issue, but ill give a brief rundown. So the inspector failed our deck this morning based on Hilti's fastener plan. I think he interpreted their fastener plan wrong, but im looking for some other opinions.

Project is using 1.5" 11/36 B-deck in Phoenix, AZ. Structural note calls for “18 fasteners per sidelap span.”

Here’s the issue:

- Joist spacing (deck support span) is ~6’-0”

- Deck sheet length (sidelap run) is ~24’-0”

Two possible interpretations:

1. 18 fasteners per 6' span → ~4" o.c. (very tight, seems excessive)

2. 18 fasteners per full 24' sidelap → ~16" o.c. (much more typical)

In your experience, when engineers reference “sidelap span,” are they typically referring to:

- the support span (joist-to-joist), or

- the full deck sheet length along the sidelap?

Also, have you seen sidelap fastening as tight as 4" o.c. for standard roof deck (non-FM extreme cases)?

Appreciate any insight—trying to determine if this is a spec ambiguity or an intentionally aggressive design.