This regards the multiplets about which we currently obtain information from Cloudy, indexed by TOTL. Specifically, the new way these are treated in Cloudy 15.

It appears C15 adds a new category of emission lines after "molecules" called "blends". It seems this has largely replaced the TOTL lines we are used to seeing, but there are some exceptions. For example, there is no longer any TOTL line around N III 1750. Here is the readout:

 Inwd      860.205A    4.359    0.0033
 N  3      1748.65A    6.367    0.3378
 Inwd      1748.65A    6.150    0.2047
 N  3      1753.99A    6.381    0.3489
 Inwd      1753.99A    6.165    0.2118
 N  3      1746.82A    5.099    0.0182
 Inwd      1746.82A    4.866    0.0107
 N  3      1752.16A    5.935    0.1250
 Inwd      1752.16A    5.709    0.0742
 N  3      1749.67A    6.719    0.7598
 Inwd      1749.67A    6.519    0.4794
 N  3      989.799A    6.761    0.8374

Instead, presumably, there is a blend line near the relevant wavelength. listed in the blends section. Blended regions can also be accompanied by an inward component. For the N III example I found

Blnd      1750.00A    7.040    1.5897

In the blends section, Cloudy also outputs lines with more specific labels, often alongside similarly-located blends. For example:

Blnd      1657.00A    6.418    0.3794
C 1R      1656.00A    6.361    0.3329
Blnd      2326.00A    5.748    0.0811
Blnd      1335.00A    7.737    7.9093
C 2R      1335.00A    7.690    7.1108
C 2P      3920.00A    4.311    0.0030
Blnd      6580.00A    5.257    0.0262

My guess is these are physically-modelled multiplets displayed alongside some sort of continuum blending. I read in the "A Multiplet Table of Astrophysical Interest" about a certain type of blending, but the document is huge and I didn't delve far into it; besides, this could be another type of blend altogether, given what I know.

So, I'm not sure how we might make sense of a blend line alongside the thought of the TOTL in C13 (which is that the TOTL should represent the sum of the multiplet values). In the N III example, the sum of the quintuplet's values does match the blend value. For C I, however, it does not.

 C  1      1656.27A    5.388    0.0354
 Inwd      1656.27A    5.380    0.0348
 C  1      1656.93A    5.390    0.0356
 Inwd      1656.93A    5.374    0.0343
 C  1      1657.01A    5.506    0.0465
 Inwd      1657.01A    5.520    0.0480
 C  1      1657.38A    5.354    0.0327
 Inwd      1657.38A    5.329    0.0310
 C  1      1657.91A    5.390    0.0356
 Inwd      1657.91A    5.374    0.0343
 C  1      1658.12A    5.417    0.0379
 Inwd      1658.12A    5.406    0.0369

 (Sum = .2237)

 Blnd      1657.00A    6.418    0.3794
 C 1R      1656.00A    6.361    0.3329


The only places I found where TOTL lines still exist are in the general properties (i.e. TOTL 4861) and the He-like iso-sequence. For example,

 TOTL      29.0840A    6.811    0.9375
 N  6      29.0840A    6.309    0.2957
 Inwd      29.0840A    6.528    0.4886
 N  6      29.0815A    3.848    0.0010
 Inwd      29.0815A    4.062    0.0017
 N  6      28.7870A    5.941    0.1266
 Inwd      28.7870A    6.062    0.1672


This example does not sum properly, either. So, I really have no idea what's going on, here. But, as we mostly decided before, it shouldn't matter much for our current purposes.