Use Ifelse on grouping after obtaining a frequency table (R)

Here is my Data.frame

New = (data.frame(ID=c(1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,3,3,4,4), 
                DC=c("Qualx","lmx", "lmx","lmx","lmx", "Qualx","Qualx","Qualx",
                     "lmx","lmx", "lmx", "Qualx", "Qualx","Qualx","Qualx","Qualx","lmx", "Qualx", "Qualx", "Qualx")))

Now I would like to group by (ID,DC), and then extract counts or frequencies(percent * 100 format)

My approach using DPLYR New1 <- New %>% group_by(ID,DC) %>% mutate(count=n())%>% mutate(freq = count / sum(count))

However, my 'freq' column seems to be displaying wrong information.

Once I do get my frequency values, I would like to mutate again, and get another column based on ifelse - something like:

%>% mutate(n = ifelse(freq == .5, DC, 'Unknown')

however, when I perform the above operation, I keep running into various errors.

I also tried:

  D_F_P <- New %>% group_by(ID,DC) %>% table() %>% data.frame() %>% mutate(freq = Freq / sum(Freq))%>%mutate(assign = ifelse(freq == .1, DC, 'Unknown'))

The above operation provides a numeric value for 'assign' column instead of returning the string value present in DC column, like this:

      ID    DC Freq freq  assign
1  1   lmx    5 0.25 Unknown
2  2   lmx    2 0.10       1
3  3   lmx    1 0.05 Unknown
4  4   lmx    0 0.00 Unknown
5  1 Qualx    4 0.20 Unknown
6  2 Qualx    5 0.25 Unknown
7  3 Qualx    1 0.05 Unknown
8  4 Qualx    2 0.10       2

Instead I want it to display

      ID    DC Freq freq  assign
1  1   lmx    5 0.25 Unknown
2  2   lmx    2 0.10     lmx
3  3   lmx    1 0.05 Unknown
4  4   lmx    0 0.00 Unknown
5  1 Qualx    4 0.20 Unknown
6  2 Qualx    5 0.25 Unknown
7  3 Qualx    1 0.05 Unknown
8  4 Qualx    2 0.10   Qualx

My main goal is to group by (ID,CD), then get frequencies (percentage*100), then use an ifelse statement that returns values in DC column. Any help would be appreciated. You don't even have to use my approach, any approach related to 'dplyr' in your personal way would also be appreciated. Thank you