Ok, training complete!
column 1: skill
column 2: skill amount on personal file of the commander when i reached the skill
column 3: skill amount on column 2 multiplied for 1.35 (to compensate hidden stats, anyway "accelerate crew training" bonus on experience seems to be shown, while stats for the first victory of the day aren't shown, then the coefficent should not be 1.35 but less)
column 4: skill predicted by the formula
on a t26 that starts with elite status and accelerate crew training on.
50 0 0 0
51 371 501 524
52 691 933 1072
53 985 1330 1646
54 1843 2488 2247
55 2072 2797 2876
56 2428 3278 3536
57 2861 3862 4226
58 3400 4590 4949
59 4082 5511 5705
60 4510 6089 6498
61 5315 7175 7328
62 6077 8204 8196
63 6407 8649 9106
64 7236 9769 10059
65 7911 10680 11057
66 8896 12010 12101
67 9336 12604 13195
68 10241 13825 14341
69 10880 14688 15540
70 11919 16091 16796
71 12583 16987 18111
72 12923 17446 19488
73 13799 18629 20930
74 14685 19825 22440
75 15935 21512 24021
77 18193 24561 27411
78 20315 27425 29226
79 21133 28530 31127
80 22855 30854 33118
81 24297 32801 35202
82 25567 34515 37384
84 28539 38528 42063
85 30683 41422 44569
86 32983 44527 47193
87 35359 47735 49941
89 36897 49811 55831
90 38185 51550 58986
91 41493 56016 62289
92 44227 59706 65748
93 46483 62752 69370
94 47687 64377 73163
95 50005 67507 77135
96 52729 71184 81294
97 56477 76244 85649
98 58919 79541 90209
99 62587 84492 94984
100 65825 88864 99984
graph:

I think that the formula is quite correct, even if it, maybe, should be scaled to match the right shown values (to avoid calculations to compensate hidden stats)
Note that is obvious that initial boost to 75% of skill is quite useful and "cheaper".
here with real stats scaled by 1.51
50 0 0 0
51 371 560 524
52 691 1043 1072
53 985 1487 1646
54 1843 2783 2247
55 2072 3129 2876
56 2428 3666 3536
57 2861 4320 4226
58 3400 5134 4949
59 4082 6164 5705
60 4510 6810 6498
61 5315 8026 7328
62 6077 9176 8196
63 6407 9675 9106
64 7236 10926 10059
65 7911 11946 11057
66 8896 13433 12101
67 9336 14097 13195
68 10241 15464 14341
69 10880 16429 15540
70 11919 17998 16796
71 12583 19000 18111
72 12923 19514 19488
73 13799 20836 20930
74 14685 22174 22440
75 15935 24062 24021
77 18193 27471 27411
78 20315 30676 29226
79 21133 31911 31127
80 22855 34511 33118
81 24297 36688 35202
82 25567 38606 37384
84 28539 43094 42063
85 30683 46331 44569
86 32983 49804 47193
87 35359 53392 49941
89 36897 55714 55831
90 38185 57659 58986
91 41493 62654 62289
92 44227 66783 65748
93 46483 70189 69370
94 47687 72007 73163
95 50005 75508 77135
96 52729 79621 81294
97 56477 85280 85649
98 58919 88968 90209
99 62587 94506 94984
100 65825 99396 99984