Adding a duplicate number - sql-server

Question

I'm currently experiencing the following problem.
If you have a look at the below test case:
declare #Count int
, #id int = 777
declare #table table
( id int identity primary key
, JCid int
, line int
, udf float )
insert into #table (jcid,line,udf)
values
(777,1,1),
(777,2,2.1),
(777,3,2.2),
(777,4,2),
(777,5,3)
select
#Count = count(left(L.udf,1))
from #table L
where L.jcid = #id
group by left(L.udf,1)
having count(left(L.udf,1))>1
select #Count
When I run this, I get the desired results of 3, however upon developing the below trigger, I can't get the count to work out correctly:
create trigger kv_trg_JobLineNumberUpdate_AW on _btblJCTxLines
after insert, update
as
declare #LineNum float
, #OldLine float
, #id int
, #Count int
, #Err nvarchar(500)
set #Err = '--------------------------';
set #Err = #Err + #Err + CHAR(10);
set #Err = #Err + CHAR(10);
set #Err = #Err + 'You are not allowed to change this Line Number!';
select
#LineNum = iLineID
, #OldLine = isnull(ufJCTxCMLineNumber,0)
, #id = iJCMasterID
from inserted
select
#Count = count(left(L.ufJCTxCMLineNumber,1))
from _btblJCTxLines L
join inserted i on left(L.ufJCTxCMLineNumber,1) = left(i.ufJCTxCMLineNumber,1)
where L.iJCMasterID = #id
group by left(L.ufJCTxCMLineNumber,1)
having count(left(L.ufJCTxCMLineNumber,1))>1
begin
if #OldLine = 0
begin
if #Count >= 2
begin
update _btblJCTxLines
set ufJCTxCMLineNumber = cast(#LineNum as varchar)+'.'+cast(#Count as varchar)
from _btblJCTxLines L
join inserted on L.idJCTxLines = inserted.idJCTxLines
end
else
begin
update _btblJCTxLines
set ufJCTxCMLineNumber = #LineNum
from _btblJCTxLines L
join inserted on L.idJCTxLines = inserted.idJCTxLines
end
end
else
begin
select
#OldLine = deleted.ufJCTxCMLineNumber
, #LineNum = inserted.ufJCTxCMLineNumber
from inserted, deleted
if (#OldLine <> #LineNum)
begin
raiserror(#Err, 16, 1)
rollback tran
return;
end
end
end
go
The ufJCTxCMLineNumber field is the duplicate number I'm looking for.
This triggers main purpose is to ensure that the ufJCTxCMLineNumber field never has duplicates.
What happens is, a user inserts a new line, when they add a new line above any current line, I want the ufJCTxCMLineNumber field to be updated to 3.1 depending on how many duplicates there is.
How would I go about getting the correct count?
Follow this link for Sample Data.