I know it is possible, while I was using SkyEdit I could enter float with up to 7 decimal places for some really good math with actor values but in CK number is rounded to 2 decimal digits. I can't even make scaling with less than a percent per skill point. I am now forced to use SkyEdit for such a trivial matter.

maybe the Creation Kit Extender, when it will be released, could address this if bethesda does not.

There's a technical limitation for 32 bit floating point values: They are limited to 7 digits you can have 1.234567 or 12345.67 but not 12345.6789. You can't even have 123456789.0 it will be stored as 123456700.0

When an interface allows you to use 7 digits, that's just an illusion, once the values are compressed into a float that precision is gone. When using scripts you can have a higher precision during the calculations, but it will be lost when you store the value.

You're right for the percentile values, though, 3 or 4 decimal digits should be no problem, the question is whether that fine distribution would make much difference for the player.

It would actually. I want to make block skill give 50% increase in block damage when at 100 skill (currently blocked damage is not affected by skill I tested it thoroughly and only is modified by 5 first tier perks and enchants) so I need to enter value = http://forums.bethsoft.com/topic/1350096-bethesda-please-increase-perk-entry-point-textbox-number-of-decimal-digits/value * (1 + block * 0.005) which is not possible becuase lowest number I can enter is 0.01. You got my point.

Hm... you're right, that makes that function much less useful than it seems.
Does it actually work when you edit it in SkyEdit?

It would make more sense for that function to actually use the skill as a percentile value (100 block = 1.00)
Doesn't seem like Bethesda used that function anywhere.

Anyway, how much damage does a shield-bash do 10? 20? 50?
If one point in the skill would increase the damage by 0.5% then the player won't notice if you simply add 5% for every 10 skill points:
Skill 10: 10 / 21 / 52 damage
Skill 20: 11 / 22 / 55 damage
Skill 30: 11 / 23 / 57 damage
Skill 40: 12 / 24 / 60 damage

Yeah it works in SkyEdit you can put up to 7 decimals and I only needed 3. It also seems that CK reads and saves the mod properly after I tweak it in SkyEdit as long as I don't try to access the perk entry in CK.

I meant whether the game actually uses the value 0.005 and doesn't round it to 0.01 or 0.

It works fine in game. It is just CK limitation.

In the CK I've noticed it rounds the values displayed after you enter them, but I'm not sure if the value its actually using is the float value you entered. For example i made a slow time spell and entered a magnitude of something like 0.00001, and in the CK box for the value it said it was 0.00. This worked when i cast it and slowed time enough that it seemed to be basically stopped, except I think arrows still moved a bit. But then another time i had the value of 0.00 and the spell wouldn't function. I just tested it again now to be sure and yes, I set the value to 0 and the slow time does nothing. I set it to 0.00001 and say okay and it tells me the value is 0 in the CK, but when I cast it ingame the spell works and stops time.

Could you use a second float to try to simulate a double? Use one like a numerator and the second like a denominator?

Of course, someone with access to the sourcecodes could do that. But then it would be easier to simply use a double. Mantissa size is not really the problem here, though.

Usually such low numbers are pointless, and the above example is one of those cases. When you increase damage by 0.5% per skill point, you need to do 200 base damage to have a measurable increase per skill point, but it won't be noticeable, so you could just as well simply add 5% per 10 skill points.

Actually health and damage values are float. You can deal 0.01 damage and have 0.01 health.