I discovered why comp #5 and #6 are included even though their adjusted values weren't used to figure the final appraisal value. So for anyone else wondering why some comps don't seem to factor into their own appraisal value at all, this could be why.
"ADJUSTMENTS ARE DERIVED FROM PAIRED SALES ANALYSIS WITH THE FINAL ESTIMATED VALUE BRACKETED WITH PRE AND POST ADJUSTED SALES COMPARABLES WITH ADDED SUPPORT FROM COMPARABLES #5 AND #6."
I had to look up "paired sales analysis" to find out it's the word for what we all know appraisals generally involve - assigning value to bathrooms, square footage, bedrooms, etc. to reach the adjusted value.
So even though their adjusted value didn't factor into the appraisal value, #5 and #6 were included because they were used (along with the other comps) in assigning values to the features.
So to recap the original info.
Appraised value: $390,000
The comps are:
Sale price - Adjusted sale price - Distance - Status
1. $390,000 - $393,900 - .8 miles - standard sale closed 11/13
2. $368,000 - $389,208 - .8 miles - standard sale closed 12/13
3. $435,000 - $430,000 - .21 miles - standard sale closed 3/14
4. $448,000 - $428,000 - .21 miles - standard sale closed 5/14
5. $419,900 - $406,502 - .21 miles - pending standard sale
6. $398,000 - $405,040 - .08 miles - active listing
From what I've gather from here and other sources, and using that to interpret the comments on the appraisal, the math appears to work out somewhere along the lines of this.
"COMPARABLES #1 AND #2 WERE GIVEN THE MOST WEIGHT DUE TO LOCATION AND CONDITION, COMPARABLES #3 AND #4 WERE GIVEN SECONDARY WEIGHT IN DETERMINING ESTIMATED VALUE FOR THE SUBJECT PROPERTY."
Only #1-#4 were used in final value. #5 & #6 were included just for getting feature values. Sentences across several sections of the comments, indicate that comps outside the community were chosen due to their proximity and similarity in community amenities with the subject.
No explanation in the appraisal as to why the value is so much closer to #1 & #2 than #3 and #4. Neither the mean, median, nor mode were used on those 4 numbers. By rounding (thanks to jackmichigan who pointed out that incredibly obvious thing I didn't even think about), #1 & #2 come out to $390,000, #4 & #5 come out to $430,000.
The appraiser possibly (tho not necessarily) took those rounded numbers and rather than doing any type of average, applied almost the entire weight to #1 and #2 due to their proximity and being in the same complex. (I would say no weight, but the comments state #3 & #4 were part of determining the final value.) Or possibly chose to do a combination of weighting and mode and decided that since there was no mode (2 at $390k, 2 at $430k means neither value occurs more often), that the weight of #1 and #2 justifies their value as valid for the mode.
The weighting was possibly (but unofficially) applied so strongly to #1 and #2 due to:
1. realizing that the contract price was $385,000 therefore the appraisal didn't need to come in any higher to satisfy the lender's concerns
2. due to history in the industry, appraisers prefer not to have appraisals come in much higher than the contact price
(thanks to berniekosar19 for the inside info and back story)
Seems justifiable enough.
Thanks to you all (even if I didn't mention you specifically) for helping to work it out!