That looks right. In both cases you'd listed PFD at the engagement, so I suspect it's just a copy and paste error.
As you know, I have an interest in the relative strengths in these battles, and find 104,100 rather high. I believe that is the number he had under command though.
Livermore gives the following on the Seven Days:
SEVEN DAYS’ BATTLES, JUNE 25--JULY 1, 1862.
UNION ARMY.
Effectives engaged:91,169
Killed, 1734. Wounded, 8062. Total, 9796. Missing, 6053.
Hit in 1000 = 107
Hit by 1000 = 216
CONFEDERATE ARMY.
Effectives in Army of Northern Virginia July 20: 60,639
Losses in the Army of Northern Virginia June 25-July 1: 18,852
Effectives in Ewell’s and Jackson’s divisions: 15,990
Total engaged: 95,481
Killed, 3478. Wounded, 16,261. Total, 19,739. Missing,875.
Hit in 1000 = 207
Hit by 1000 = 102
Livermore is lucky in that all the CS commanders gave their musket strength (except RH Anderson and Featherston, and the cavalry and artillery). He is less lucky in the Union Army, and is using the PFD, deducting 7% for non-effectives. Thus he's overestimating the Union strength more than Confederate (but is trying to be consistant at least).
So
(U:C)
Ratio of starting strength:0.955:1
Ratio of final strength: 1:0.994
Ratio of casualties: 1:2.015
Ratio of casualties and missing: 1:1.301
Implied CEV using case most favourable to Lee (which is actually the best measure): 1.32 in the Union favour (i.e. roughly 3 Yankees had the same combat power as 4 Rebs).
Livermore on Williamsburg:
WILLIAMSBURG, MAY 4, 5, 1562.
UNION ARMY.
Effective strength,” estimated at 93 per cent. of the number &‘ present for duty,” which is assumed to be 34 of the number present for duty in 3d and 4th corps: 40,768
Killed, 456. Wounded, 1410. Total, 1866. Missing, 373.
Hit in 1000,45. Hit by 1000,39.
CONFEDERATE ARMY.
Effective strength,* May 21 1862, of the divisions of Longstreet and Hill, and the brigades of McLaws, Kershaw, and Stuart: 30,120
Add loss May 4,5 . . . . . . . . . . . 1,703
Total engaged . . . . . . . , . . . 31,823
Killed and wounded, 1570, Missing, 133.
Hit in 1000, 49. Hit by 1000, 59.
Fair Oaks:
FAIR OAKS, MAY 81, JUNE 1, 1802.
UNION ARMY.
24 3d, and 4th corps present for duty May 31: 51,543
deduct 3d corps cavalry, 751, and 8 regiments and 5 batteries, estimated at 5848, not engaged . . . . -- 6,599
= 44,944
Effectives estimated at 93 per cent: 41,797
Killed, 790. Wounded, 3594. Total, 4384. Missing, 647.
Hit in 1000,105. Hit by 1000,137.
CONFEDERATE ARMY
Effective strength of Smith’s, Longstreet’s, and Hill’s divisions, May 21: 35,559
Effective strength of Huger’s division (3 brigades), estimated: 6,257
Total effective: 41,816
Killed, 980. Wounded, 4749. Total, 5729. Missing, 405.
Hit in 1000, 137, Hit by 1000, 105.