TDS on salary

Yes, employer can deposit the same in next month.

Income tax computation
is not being calculated like that.
Its deducted on the basis of income earned by the assesse in the financial year.
The threshold limit is there.
admissible allowances and exemptions.
rest u calculate.

Employer should immediately deduct TDS as early as possible that is on next salary when TDS was under deducted or forgotten in any earlier months

A projection is given at the beginning of every financial year.
Accordingly the designated staff calculates tax after considering all investment by the employee.
If the tax liability is huge which is only applicable in case of employee who are in higher tax bracket say above ten lakhs annually.
for them the designated staff has to deduct tax every month.
In any other caees there can be adjustments.

1. TDS if not deducted by an employer for one month by mistake will be deducted the next month together. 
2. If TDS is deducted for next month (including previous month) the same will be shown under NSDL site only the month in which the TDS was deducted. If TDS not deducted it will not be shown under NDSL site. 
Please correct me if the above solution has an alternative view.