Formula Round Up The Values

I am using Excel as my payroll spreadsheet
A....name
B....rate of pay
C....date of work
D....date of work
E...date paid
F....# of hours worked
G....vacation hours
H....Gross Pay....B7*(F7+G7)
I....Net Pay....H7-J7-K7-L7-M7-N7
J....FICA....H7*6.2%
K....Federal....no formula
L....State.....no formula
M...Medicare....H7*1.45%
N....duductions....no formula
O....OT...no formula
P....Paid OT....O7*15.75
Q....Blank
R....FICA MATCH....J7*2
S....Medicare MATCH....M7*2 (ISN'T ROUNDING UP OR DOWN PROPERLY)

For Instance.......Joe worked 19.58 hours at $8.50 = $166.43 gross
federal is $0
state os $0
fica is $10.32
medicare is $2.41
R...FICA Match is $20.64
S...Medicare Match is $4.83.....(SHOULD BE $4.82)

Sorry but I didn't know how to properly explain the problem that I am having. The problem is in the rounding. Sometimes it doesn't round up and sometimes it doesn't round down.