line 3a of AMT form 1116

[tax1111]

I used different tax softwares and all of them shows 0 on line 3a (certain itemized deductions or standard deduction) of AMT form 1116 when taxpayer uses standard deduction. Is this correct?

Based on 1116 instructions, when taxpayer uses standard deduction, line 3a for regular form 1116 should show standard deduction amount. But the instruction does not explicitly say that standard deduction amount should be input on line 3a of AMT form 1116. 

Should I assume the tax softwares are correct or should I manually input standard deduction on line 3a of AMT form 1116?

Thank you!