USA 1940 census references

Hi Peter,
It looks like I'm doing something wrong.
After I enter a household on the My Ancestors page using the USA 1940 census, the link arrow <Click to check against the census> doesn't come up.
Your guidance says: "Some sources of the 1940 Census give all the census references in the transcription, but for others you'll need to refer to the image - you'll find the Enumeration District (ED) and Sheet number at the top right. When FamilySearch refer to 'Affiliate' they mean the NARA. NARA Roll Number: do NOT include T627 prefix if shown."
I looked at the images and the transcriptions on all 3 sites: familysearch; national archives (NARA); ancestry (com and co.uk).

• The images show E.D No. 17-5, Sheet No. 2B, but not the NARA Roll number, even if you scroll to the 1st or last image of the set.
• The familysearch transcription page doesn't give references, or mention affiliates, but just points to a description of the Enumeration District.
• The NARA site doesn't seem to provide transcriptions or references, but gives link to a helpful site "Universal 1940 Census Image Viewer", run by Steve Morse. That comes up with: California | 17.Lake County | ED 17-5 | Image 4 (Roll 218 Frame 108).
• The Ancestry site shows: Roll: m-t0627-00218; Page: 2B; Enumeration District: 17-5.

So I enter NARA roll number as 00218, but the box accepts only 4 digits max and displays 0218.
The reference then appears OK on the lostcousins My Ancestors page as 218/17-5/2B, but without the link arrow.
Thanks for any light that you or others can throw on this small problem.

 

Many thanks, Peter: exactly what I needed to know.
Still can't find the NARA Roll # anywhere on the familysearch site, but no matter.