BUG in options article by Fidelity & CBOE from 2013 :-)

[earth_imperator]

Spotted a BUG in an options article by Fidelity & CBOE from 2013

This is the buggy article: "Long calendar spread with puts"
https://www.fidelity.com/learning-c...ions-strategy-guide/long-calendar-spread-puts

I wonder how such big companies can make such silly errors.
Moreover that in all the years since 2013 (9+ yrs!) nobody on Earth spotted this error!... except me...

Their disclaimer:
"Article copyright 2013 by Chicago Board Options Exchange, Inc (CBOE). Reprinted with permission from CBOE. The statements and opinions expressed in this article are those of the author. Fidelity Investments cannot guarantee the accuracy or completeness of any statements or data."


The screenshot below is from the linked article.
The error is in the table: the row for Spot 100 is wrong, IMO, and maybe even some more is wrong in the article:

 

[earth_imperator]

Can someone tell me what the margin requirement would be for the above LongPutCalendarSpread
(aka PutCalendarBullSpread ?) consisting of:
ShortPut: K=100 DTE=28 Premium=3.25
LongPut: K=100 DTE=56 Premium=4.60
Is it the absolute value of the said net cost of -1.35 (= 3.25 - 4.60), ie. 1.35 ?

 

[earth_imperator]

Here the correct values for the above buggy table in the article.
Especially the result for Spot 100 differs big: 1.9244 vs. 0.90 in their table. Ie. the buggy row.
As stated in the footnote of them: IV=30 and r=1% and q=0% has been used for the LongPut at expiry of the ShortPut:

115.0000: S(Pr=0.0000   PL=3.2500  ) L(Pr=0.1663   PL=-4.4337 ) --> PL=-1.1837 
110.0000: S(Pr=0.0000   PL=3.2500  ) L(Pr=0.5339   PL=-4.0661 ) --> PL=-0.8161 
105.0000: S(Pr=0.0000   PL=3.2500  ) L(Pr=1.4433   PL=-3.1567 ) --> PL=0.0933 
100.0000: S(Pr=0.0000   PL=3.2500  ) L(Pr=3.2744   PL=-1.3256 ) --> PL=1.9244 
 95.0000: S(Pr=5.0000   PL=-1.7500 ) L(Pr=6.2703   PL=1.6703  ) --> PL=-0.0797 
 90.0000: S(Pr=10.0000  PL=-6.7500 ) L(Pr=10.3144  PL=5.7144  ) --> PL=-1.0356 
 85.0000: S(Pr=15.0000  PL=-11.7500) L(Pr=14.9982  PL=10.3982 ) --> PL=-1.3518