Digital BW, The Print

I'm printing wy UT14 and icc profiles (i find very good the approach of paul roark - thank you Paul!).
After printing with Photo Rag and Epson archival matte I try to print on Ilford Gold Silk.
It is my firs glossy paper and I'm tring to understand how I have to use this kind of papers.
I star with the warm acv curve that I find in the sample of Paul and I can have a very good starting point.
But if I read a 21 step printed with this acv curve I obtain these values:
4,05	-7,13	-9,53
96,70	2,17	-3,34
91,57	2,16	-3,12
85,44	2,22	-2,95
80,36	2,50	-2,40
74,96	2,63	-1,86
69,55	2,83	-1,31
64,16	2,95	-0,87
59,14	3,14	-0,27
54,04	3,40	0,27
49,73	3,56	0,94
45,46	3,96	1,32
41,57	4,04	2,11
36,61	4,09	2,85
31,31	4,69	3,49
25,71	4,85	3,17
21,65	4,98	2,50
17,78	4,59	1,61
13,64	4,45	0,53
11,18	4,65	0,70
11,08	3,57	2,37

I think that the numbers on first line are not correct.
I try to measure with datacolor spyder print some white ilford paper and I find always a value that is for a black, not for a white (exact the first line that you can see).
Is a problem of datacolor spyderprint or I'm loosing something?

I have another little question: for making icc profiles I start with a 21 step file in RGB mode. This mode I need for the color separation acv curve.
The ICC profile that i obtain from this file can be used also for printing gray scale file or only RGB files?

Thank you

Marco