Minimum Strength required?

Hi all,
I'm making a new cleric (as I mainly PvE, and further research showed my LA build wasn't really the best at that), and was once again looking over the builds. I decided to do 8 mag 1 str 1 vit (4 mag 1 vit/4 mag 1 str), only I have trouble keeping track of which I was supposed to raise whenever I leveled. b:embarrass

So I pulled out a spreadsheet and went to the database, and scribbled down numbers. Going through that, it doesn't look like it's +1 Str every 2 levels. Somebody tell me if I'm very wrong?

Armor			
Level	Str	Grade	
1	5	1	Arcane Headgear
1	5	1	Arcane Robe
2	5	1	Arcane Leggings
3	5	1	Arcane Wristguards
4	5	1	Arcane Footwear
5	6	2	Arcane Robe
6	6	2	Arcane Headgear
8	7	2	Arcane Leggings
9	7	2	Arcane Wristguards
10	7	2	Arcane Footwear
12	9	3	Arcane Robe
13	9	3	Arcane Headgear
15	10	3	Arcane Leggings
16	11	3	Arcane Wristguards
18	11	3	Arcane Footwear
20	14	4	Arcane Robe
21	15	4	Arcane Headgear
23	16	4	Arcane Leggings
24	16	4	Arcane Wristguards
26	17	4	Arcane Footwear
30	19	5	Arcane Robe
31	20	5	Arcane Headgear
33	21	5	Arcane Leggings
34	21	5	Arcane Wristguards
36	22	5	Arcane Footwear
40	24	6	Arcane Robe
41	25	6	Arcane Headgear
43	26	6	Arcane Leggings
44	26	6	Arcane Wristguards
46	27	6	Arcane Footwear

Weapons			
Level	Str	Grade	
1	5	1	Wand
2	5	1	Magic Sword
3	5	1	Pataka
4	5	1	Glaive
5	6	2	Wand
7	6	2	Magic Sword
9	7	2	Pataka
11	8	2	Glaive
13	9	3	Wand
15	10	3	Magic Sword
17	12	3	Pataka
19	12	3	Glaive
21	14	4	Wand
24	16	4	Magic Sword
27	19	4	Pataka
29	19	4	Glaive
31	18	5	Wand
34	21	5	Magic Sword
37	24	5	Pataka
39	24	5	Glaive
41	23	6	Wand
44	26	6	Magic Sword
47	30	6	Pataka
49	29	6	Glaive

Compiling the Level/Str and sorting, then just keeping the earliest strength raises gives me:

Level	Str
5	6
8	7
11	8
12	9
15	10
16	11
17	12
20	14
21	15
23	16
26	17
27	19
31	20
33	21
36	22
37	24
41	25
43	26
46	27
47	30

If I go Str +1 every 2 levels, at level 5 I have 7 Str, which is more than necessary. At level 8 I'll have 8-9 Str, still more than necessary. By level 11 I'll have 10 Str, by level 15 I'll have 12 Str.
It looks like that, at least early on, I don't need to follow this formula.
At level 21 though, I'll have 15 Str (min necessary), and it matches at 31 as well.

However, at level 31 I need 20, but I only need 19 at level 27. So I can in fact wait until actually reaching level 31 and using that level to get it to 20.

...is this just putting too much thought into it? If I follow this chart, it means every few levels I'll have more Mag then anyone simply following a build, and then spend a level catching up in Str. Worth it? b:puzzled