
SECTION
17.5
After-Tax PW,
AW,
and ROR Evaluation
flows. (The only exception, mentioned in Section 8.5, occurs when the AW
anal ysis
is
performed on actual cash flows, not the increments; then one-
life-cycle analysis is acceptable over the respective alternative lives.)
Revenue
and
service
alternatives:
Revenue alternatives (positive and nega-
tive cash ftows) may be treated differently from service alternatives (cost-
only
cashftow
estimates).
For
revenue alternatives, the overall
i*
may be
used to perform an initial screening. Alternatives that have
i*
<
MARR
can be removed from further evaluation. An
i*
for cost-only (service)
alternatives cannot be determined, so incremental analysis is required with
all alternatives included.
These principles and the same procedures developed in Chapter
8 are applied
to the CFAT series. The summary table
in
the rear
of
the
book
(which is also
Table
10
- 2) details the requirements
of
all evaluation techniques. For the
ROR
method,
in
the column labeled "Series to Evaluate" change the words cash flows
to CFAT values. Additionally, use the after-tax
MARR
as the decision guideline
(far right column). Now, all entries for the
ROR
method are correct for an after-
tax analysis.
Once the CFAT series are developed, the breakeven ROR can be obtained
using a plot
of
PW vs. i*. Solution
of
the
PW
relation for each alternative over
the
LCM
at several interest rates can be accomplished by hand
or
by using the
591
NPY spreadsheet function.
For
any after-tax
MARR
greater than the breakeven
(-/-----
--0
ROR, the extra investment is not justified. [ PW
vs.
i*
.
Example
17
.9 illustrates an after-tax
ROR
evaluation
of
two alternatives
'----
------'"
solved by hand.
The
next section includes additional examples solved by com-
puter using incremental
ROR
analysis and the breakeven plot
of
PW
vs. i*.
EXAMPLE
17.9
.
Johnson Controls must decide between two alternatives in its northeast plant: sys-
tem
I-a
single robot assembly system for lCs will require a $100,000 investment now;
and system
2-a
combination of two robots requires a total
of
$130,000. Management
intends
to
implement one
of
the plans. This manufacturer expects a 20% after-tax return
on
technology investments. Select one
of
the systems, if the following series
of
cost
CFAT
values have been estimated for the next 4 years.
System 1
CFAT,
$
System 2
CFAT,
$
Solution
o
- 100,000
- 130,000
1
-35,000
- 20,000
Year
2 3 4
-30,000 -20,000 -15,000
- 20,000
-10,0
00
-5,000
System 2
is
the alternative with the extra investment that must be justified. Since lives
are equal, select
PW
analysis
to
estimate
t:.i*
for the incremental
CFAT
series shown
here.
All
cash
flows
have been divided
by
$1000.